Heifer

Stop the Guesswork: Build a Targeted Parasite Plan

Mon, 04 May 2026 13:51:51 GMT

As grass greens up and cattle head back to pasture, many producers are “throwing darts in an open field” when it comes to parasite control, says Tennessee Hereford breeder Ryan Proffitt.

The real-world frustration of deworming programs is knowing if they are working, Proffitt says.

Norbrook Technical Services Veterinarian Megan Bollin explains fecal egg count testing, targeted treatment, concurrent deworming, maintaining refugia and smarter pasture management can turn parasite control guesswork into a targeted plan that protects herd health, preserves dewormer efficacy and ultimately adds pounds to the calf crop.

Both Bollin and Proffitt agree a pragmatic roadmap for modern parasite control is anchored in diagnostics, targeted treatment and strong relationships with veterinarians.

Bollin shares five practical strategies to get the most out of today’s dewormers and preserve them for tomorrow:

1. Sit Down with Your Vet.

She encourages producers to map out a herd‑specific internal and external parasite plan with diagnostics built in.

“Your local vet should be your key partner in designing a program that fits your parasites, climate and management style,” Bollin says.

2. Use the Right Product at the Right Time.

Use the correct class, correct dose and consider concurrent deworming when resistance is a known issue. Your local veterinarian can guide you on proper treatment timing to avoid wasting money.

3. Manage Pastures with Parasites in Mind.

Bollin says pasture management is as important as treatment. Pasture type, quality, topography and drainage should all be considered in your plan, knowing we can’t always do much to change them.

“Only about 10% of the parasite life cycle is in the animal; 90% is on pasture,” she says.

Larvae generally stay below 4” on the grass blade. She says it is important to avoid overgrazing pastures below this height and manage stocking density accordingly.

“When you get a big rain after a drought, the larvae that had been waiting in the manure pats can quickly become infective and significantly increase the risk of infection, especially in young calves,” she says.

4. Prioritize High-Risk Animals.

Calves, stockers, bulls and replacements should be prioritized with the strictest parasite control and monitoring programs.

“Calves, replacement heifers and bulls are typically heavier shedders and more susceptible to the effects of parasites than mature cows,” Bollin explains.

Proffitt notes that many producers historically concentrate on keeping mature cows dewormed while underestimating calves’ role as carriers.

“We don’t need to, and shouldn’t be, treating every animal like we always have,” Bollin adds. “That has gotten us in a pickle with resistance.”

5. Measure and Adjust Treatment.

Bollin says it is important to know where you started. Get a baseline fecal egg count, understand your resistance patterns and monitor the efficacy of your treatment program. So many variables change from year to year: climate, weather conditions, new animals and other stressors. It’s critical to routinely evaluate your deworming program and avoid blindly doing the same thing year after year.

(Proffitt Family)

Diagnostics Are Essential, Not Optional

Fecal egg count reduction tests (FECRTs) are the most practical method we have to determine if dewormers are still working and at what level.

Bollin explains the process includes:

Collecting rectal fecal samples and recording identification.
Treating animals with product or products of choice.
Resampling the same animals by taking rectal fecal samples, 10 to 17 days later, depending on the drug or drugs used.

The lab will count how many eggs per gram are in that fecal sample. There will be a pretreatment and a posttreatment sample. Bollin says the goal should be greater than 95% reduction.

Proffitt argues FECRTs are worth the hassle.

“If we don’t have a game plan on what we’re doing and we’re just rushing,” he says. “What did we win at the end of the day if we don’t know what we’re doing?”

Proffitt says testing tells him which cows he can skip treating, which saves him money.

Bollin explains in many cases mature cows 3 years and older, shedding low levels of eggs, on a good plane of nutrition, with no other stressors or health concerns (including liver flukes), should not need to be dewormed.

“This supports ‘refugia’ — intentionally leaving low-risk animals untreated to slow resistance,” she explains. “Because they’re mature, they’ve got a competent immune system that can actually fight off these parasites by themselves without a dewormer.”

To reduce costs further, Bollin says producers can pool fecal samples from multiple cows into a single submission.

(Deb Gustafson)

Beating Parasite Resistance Starts at the Chute

Bollin says dewormer resistance, long documented in sheep and goats, is being seen more frequently in U.S. cattle herds.

She says overuse, underdosing and treating every animal regardless of need are major drivers in resistance.

“All of these deworming products, when they were originally approved, had very high levels of efficacy. We’re talking 99% and above,” Bollin explains. “As we’ve continually used these products, efficacy has been challenged because resistance has increased.”

If you’re using products that are no longer effective in your herd, you’re spending money on drugs that don’t work, and you’re not getting the production benefits. One way to restore efficacy when resistance is present is to use concurrent deworming.

Why Concurrent Deworming Matters

Bollin says concurrent deworming is using two dewormers from different classes at the same time. She stresses producers need to work with a veterinarian to avoid unknowingly pairing two products from the same class, which doesn’t provide the intended benefit.

She explains the benefits of concurrent deworming are:

· Higher overall efficacy when two partially effective products are combined. “Say you’ve got two products, for example, each with 70% efficacy. By using them together, you can raise your overall efficacy to levels exceeding 90%,” she says.

· Broader spectrum of parasite coverage.

· Models would suggest a slowing of resistance.

· Only sustainable long-term when used in conjunction with a refugia program. This means we don’t treat every animal. We want to keep a few “good” worms around that are still susceptible to the drug.

Bollin gives the example of pairing a benzimidazole, or a “white dewormer,” such as fenbendazole, albendazole or oxfendazole, with a macrocyclic lactone such as ivermectin, moxidectin or eprinomectin.

She emphasizes the industry unfortunately doesn’t have a lot of studies looking at this, but a study published in 2025 highlighted the benefits of concurrent treatment with fenbendazole in situations where resistance to macrocyclic lactones is likely.

Dung Beetles Are Valuable Allies

Dung beetles break up manure pats, exposing eggs and larvae to sunshine and dry conditions. Some dewormers are more compatible with dung beetle health.

“Two of the dewormers that are not harmful are moxidectin and fenbendazole,” Bollin says. “Those are two molecules that are generally safe for dung beetles, and those could be a good option to pair together.”

Facility where researchers collect blood samples and weigh cattle before and after they are transported. Steers have painted numbers on their backs so their activity can be followed on camera.

(Stephanie Hansen)

Application Technique and Dosing Accuracy Matter

Bollin says accurate body weights, not visual estimates, are critical, explaining underdosing is a key driver of resistance.

“One of the biggest contributors to resistance is that we are just not giving them enough active ingredient,” she says. “If you don’t have scales, it is best to treat to the heaviest body weight in the group, so that you make sure that they’re all getting enough.”

She also stresses the importance of storing deworming products correctly.

“Leaving them by the chute in temperature swings can reduce efficacy,” she says.

Proffitt also reminds producers to read labels and understand rain windows with pour-ons and to avoid mud or manure on hides. Bollin notes that injectables can provide more certainty that the animal is getting the full dose, whereas oral drenches can be spit out and pour-ons can run off or be groomed off by penmates.

Both Bollin and Proffitt frame parasite control not as one more chore on an overloaded to-do list but rather as a strategic, data-driven opportunity to protect animal health, slow resistance and convert good management into pounds sold.

Your Next Read:

Determine Parasite Load and Follow With Treatment

Does Supplementing Bred Heifers Increase Calving Difficulty?

Sat, 14 Feb 2026 00:27:46 GMT

Producers are often told supplementing bred heifers with protein prior to calving increases calf birth weight and leads to greater calving difficulty.

According to Paul Beck, Oklahoma State University (OSU) Extension beef cattle nutrition specialist, nutrition of bred heifers during gestation does have lasting consequences for both the calf and the future productivity of the cow.

“Decades of research clearly demonstrate that maternal undernutrition during pregnancy negatively influences not only the cow’s reproductive performance, but also immune transfer, calf survival, weaning weight and post-weaning performance,” he says.

Research conducted in the 1970s at OSU compared productivity of heifers managed to achieve either adequate or obese body condition from 12 months through 5 years of age. At first calving, 58% of the obese heifers required calving assistance, compared with only 8% of heifers at adequate body condition. These data are the basis for current recommendations that heifers calve at a body condition score (BCS) of approximately 6, but not reach a fleshy (BCS 7) or obese (BCS 8) condition.

Energy and protein supply during late gestation can influence calf birth weight, Beck summarizes. Research by Corah and colleagues published in 1975 demonstrated heifers restricted to 65% of energy requirements during the final 100 days of gestation produced calves approximately 4.4 lb. lighter at birth. However, these calves experienced greater neonatal mortality and reduced weaning rates compared with calves from adequately fed dams. Importantly, lighter birth weight was not associated with reduced calving difficulty, illustrating how undernutrition compromises calf viability rather than preventing dystocia.

“Restricting nutrients prior to calving weakens both the cow and the calf, increasing calving difficulty and reducing calf survival,” Beck summarizes.

Kansas State University’s Jaymelynn Farney says restricting heifer diet in the last trimester can result in potentially lower quality and quantity of colostrum , reduced absorption of immunoglobulins from colostrum potentially driven by weaker calves that were slower to nurse, an increase in calf scours and a reduction in overall weaning weights.

Birth weight responses to precalving supplementation are highly variable. Beck evaluated changes in calf birth weight reported from 24 studies evaluating late-gestation supplementation.

“The average increase in calf birth weight was only 3 lb., with responses ranging from a 3 lb. decrease to a 10 lb. increase,” he reports. “The largest increases occurred when high levels (approximately 5 lb. per day) of energy-dense supplements were fed.”

Fifteen of these studies also reported subsequent pregnancy rates. Although variable, the average pregnancy rate of unsupplemented cows was 86%, compared with 92% for cows supplemented during late gestation, with the greatest response observed in first-calf heifers.

Excessive energy intake during late gestation partitions more nutrients toward fetal growth, resulting in larger calves. When coupled with excess fat deposition in the pelvic region, this increases the risk of dystocia. Thus, excessive energy, rather than protein supplementation alone, is the primary contributor to increased calving difficulty in many heifer programs.

Ensuring bred heifers meet — rather than greatly exceed — energy and protein requirements, promoting moderate BCS gain during mid and late gestation and strategically supplementing key nutrients improves calf survival, preweaning growth, immune function and long-term reproductive performance without increasing calving difficulty.

“Avoiding maternal undernutrition remains one of the most consistent strategies for improving whole-herd productivity and profitability,” Beck summarizes.

What Causes Calving Difficulty?

Farney says there are multiple reasons calving difficulty can occur, which may include the calf being too big, pelvis too small, abnormal presentation, lack of uterine contractions, fatigue or twins.

“Abnormal presentations cannot be eliminated by genetic selection or nutritional management, so be prepared for these scenarios a minimum of three weeks before your first calf is expected,” says Farney, a beef systems specialist.

Calf birth weight is often blamed as the sole culprit of calving issues.

“Calf birth weight can be affected by several factors — genetics, gestation length and, to an extent, dam nutrition,” Farney summarizes. “High calving ease sires typically have a shortened gestation length, hence the reason that most of those calves are a bit lighter in weight.”

She says on average, calves will gain between 1.5 lb. to 2 lb. of body weight in late gestation. For example, if the average gestation length is 283 days and a calf is born a week early, it will often weigh 10 lb. to 14 lb. less.

She adds dams that experience cold stress in the last trimester may have calves that are heavier in weight.

“Typically birth weights are greater for calves born in the spring or winter as compared to fall-born counterparts,” she says. “A Nebraska study that evaluated six years of data found for each 1° F lower than the average winter temperature (December through February) calf birth weight increased 1 lb.”

The increase in birth weight is most likely due to the needed increase in nutrient flux through supplementation to offset cold stress events.

“Now you might think, it is a cold winter and I do not want to deal with calving problems, so I will just make that cow survive on the same diet she has been on and not account for added maintenance requirements due to cold stress,” Farney says. “That thought will lead to a plethora of other issues that can extend through that calf’s entire productive life.”

She stresses it is important to appropriately balance a diet for first-calf heifers.

“Don’t starve the calving difficulty out of your heifers,” Farney summarizes. “These heifers need appropriate energy to help with the birthing process or they will quit on you as they just run out of steam going through parturition. Additionally, the calves need enough energy to quickly get up and nurse, and if dam energy is restricted, calves will be lethargic. Proteins are essential for colostrum quality, which has major lifetime effects on that calf.”

Your Next Read: Feeding at Dusk: How Does This Affect Calving Times?

Rebuilding the Herd From the Cow Up

Tue, 03 Feb 2026 21:25:42 GMT

In cow-calf systems, many of the factors that determine productivity, fertility and longevity are set long before a replacement heifer ever enters the breeding pasture. The biological foundation of the cow is shaped in utero through the interaction of genetics, nutrition and environmental conditions. Those early influences follow her for life.

This was the topic of discussion during a joint presentation by Ron Scott, director of beef technical innovation at Purina, and George Parry, research professor of beef cattle reproductive physiology at Texas A&M, during CattleCon.

“We’re talking about rebuilding the cow herd, how it’s going to impact future replacement health,” began Scott, speaking on the epigenetics of heifer development. “The biggest thing we need to remember is that life really shapes the animal. It’s the environment, it’s the nutrition, it’s the genetics. All of that comes together to impact how that animal is going to perform.”

Reproductive traits offer a clear example of how the environment affects performance. While genetics matter, reproductive performance becomes less heritable as animals age because management and environment increasingly shape outcomes. Traits measured early, such as ovarian follicle number or age at puberty, are more strongly tied to inherent potential because outside influences have not yet accumulated.

Identical genetics alone do not guarantee identical performance. Animals with the same genetic makeup can diverge dramatically depending on how their genetic potential is expressed. That process begins before birth.

Fetal Development Sets Reproductive Capacity

“For that first month of life, that embryo lives totally on what’s being secreted into the environment. It’s not attached to the uterus to draw the nutrients it needs,” Parry explains. “It’s really dependent on what we’re supplying it. So what happens when we change that supply?”

Nutritional changes around breeding and early pregnancy can affect embryo survival, developmental rate and long-term function. Even when embryos survive short-term nutritional restriction, their development may already be altered.

Speaking about recent research, Parry emphasized the importance of a constant nutrient supply.

“If we drop nutritional supply at AI for as short as six days, we impact the stage of embryo development. We impact embryo quality,” he says.

One of the most critical developmental outcomes affected during gestation is ovarian reserve. Germ cells migrate and form the future ovary early in pregnancy, and the population of follicles expands and then declines before birth.

“The ovarian reserve that follows that ovary of your future replacement heifer is really impacted while that calf is in utero,” Parry says.

The number of follicles a heifer carries into life — the foundation of her reproductive capacity — is largely determined before she is born.

Importantly, these changes are not obvious at birth. Calves may look identical at birth and weaning, yet differ significantly later in reproductive performance. Heifers that experienced more favorable fetal nutrition are more likely to calve earlier in their first season, a difference that compounds across their lifetime.

Early Conception Compounds Herd Profitability

Heifers that conceive and calve early tend to remain earlier in subsequent breeding seasons. Over time, this translates into more calves, more total pounds weaned and longer productive lives. Each missed estrous cycle pushes a cow later in the calving season, resulting in lighter calves and increasing the likelihood of eventual culling.

This also impacts the bottom line.

“At $4 calves, every heat cycle you miss is worth $150”, Scott says.

Late conception often becomes a repeating pattern rather than a one-time event. Once cows fall behind, it is difficult to move them forward without intervention. Over multiple years, this drift erodes herd productivity and profitability.

Nutrition Must Be Consistent, Not Reactive

One of the strongest drivers of developmental programming is consistent maternal nutrition. Cows prioritize nutrients toward maintenance and survival first, followed by growth and lactation. Reproduction falls lower on that hierarchy. When nutrients are limited, reproductive processes and fetal development may be compromised.

“Think about consistent nutrition. That’s how you optimize,” Scott says.

Body condition score is the most practical indicator of nutritional adequacy. Gradual weight loss is difficult to detect visually, especially when cows are observed daily. Regular body condition scoring and documentation are essential for identifying trends before they become biologically costly.

Stress compounds nutritional effects. Cold weather, poor forage conditions, social pressure or environmental stressors add to the nutrient demands placed on the cow. Nutrition cannot fully offset stress, but inadequate nutrition magnifies its impact.

Heifers Require Different Management

First-calf heifers face unique challenges. They are still growing while simultaneously lactating and preparing to breed again. Treating them nutritionally like mature cows often leads to lower body condition, delayed cycling and late conception.

“Rethink heifer management. Focus on first service because of selection and conception. We need to optimize field programming,” Scott advises.

Managing heifers as a distinct group separate from mature cows allows nutrition and management to better match physiological demand. Without this adjustment, even genetically superior heifers are at risk of early failure.

Key Considerations When Selecting Replacement Heifers

Selecting replacements based solely on size or appearance at weaning overlooks critical developmental signals. Both Parry and Scott agree effective replacement selection should consider:

Calving timing: Heifers born early in the calving season are more likely to conceive early and remain productive longer
Developmental history: Maternal nutrition and stress exposure during gestation influence lifetime fertility
Growth pattern: Consistent, adequate growth is more important than compensatory gain
Body condition at breeding: Heifers must enter breeding with sufficient reserves to support cycling and conception
Reproductive readiness: Reproductive tract maturity provides insight into breeding potential
Longevity potential: Early-conceiving heifers are more likely to stay in the herd and repay development costs

Longevity is a Management Outcome

“To break even and realize the benefits of fetal programming, cows need to remain in the herd. It really starts with heifer development,” Scott says.

Longevity is not accidental. It reflects the cumulative effects of early development, nutrition, reproductive success and stress management. Developmental programming establishes the foundation, but realizing that potential requires keeping cows healthy, fertile and in the herd long enough to return value.

Putting the cow first — starting before birth — shifts herd improvement from short-term correction to long-term strategy. When early development is supported and replacement selection reinforces those advantages, productivity and profitability follow.

Fewer Heifers Mean Higher Stakes for Reproduction

Tue, 06 Jan 2026 22:01:58 GMT

Over the last 20 years, reproduction in dairy herds has changed in ways that were hard to imagine two decades ago. Pregnancy rates that once sat in the low teens are now climbing to levels that have reshaped how farms manage breeding decisions.

“We’ve seen average preg rates go from 13% to 14% to herds that now push 40%,” says Paul Fricke, professor and Extension specialist at the University of Wisconsin-Madison, on a recent Dairy Health Blackbelt podcast. “That’s why we’re using sexed semen and beef semen. It’s changed everything.”

However, that progress comes with a tradeoff. As sexed semen is used more strategically and beef semen fills in elsewhere, farms are raising fewer replacement heifers. According to Fricke, that makes it harder to absorb mistakes.

“My argument has been we’ve got to be better with those fewer heifers from a reproductive standpoint,” he says.

With fewer heifers in the pipeline, every breeding decision carries more weight. Missed heats, mistimed inseminations or extended days open can quickly add cost and delay animals entering the milking herd. Fricke says heifer reproduction can’t be treated as a low-priority task. Getting heifers pregnant at the right time, he says, matters more when fewer replacements are available.

Rethink Timed AI in Heifers

As farms work to manage heifer breeding more consistently with fewer replacements, many have turned to synchronization programs to simplify decisions and reduce reliance on heat detection. Timed-AI protocols are now common on many farms because they’re easier to manage with limited labor, but Fricke says they aren’t without limitations. He points to the 5-day CIDR-Synch protocol as a common starting point for heifers, noting that its biggest challenge comes down to timing.

“The big problem with these protocols is they’re not 100% timed AI protocols,” Fricke explains. “We’ll see about 27% to 33% of heifers coming to heat a day early.”

That early estrus creates management challenges and opens the door to mistimed inseminations. To address it, Fricke’s team tested a simple change by leaving the progesterone insert in place for an extra 24 hours.

“There were 12% of the heifers that came into heat early on the 5-day treatment, compared with only 1% on the 6-day treatment,” he says. “With conventional semen in Holstein heifers, there was no decline in fertility.”

Does Sexed Semen Need a Different Approach?

That consistency, however, doesn’t always carry over when sexed semen is used. Fricke says many farms manage sexed semen the same way they would conventional semen, which can lead to lower conception rates than expected.

“Sex[ed] semen is quite different,” he says. “What I generally see is low conception rates. I think it’s a timing of insemination issue.”

In a Wisconsin study across three farms using sexed semen, once-daily heat detection with prostaglandin achieved a 45% conception rate. The 5-day CIDR protocol improved conception to 52%. But the 6-day protocol fell back to 45%.

“The worst thing you can do with sex[ed] semen is inseminate too early,” Fricke says. “And that’s what we did. We kind of set them up to get bred too early.”

Look Beyond Upfront Costs

While synchronization protocols often draw scrutiny for their upfront cost, Fricke argues that focusing only on protocol price misses the bigger economic picture. The real driver of profitability in heifer reproduction, he says, is days on feed.

“The big thing about repro in heifers is limiting total days on feed, because total days on feed is determined by when you get the heifers pregnant,” he says. “That feed cost is something that a lot of farmers don’t look at. It’s the classic kind of unfunded cost, right? The hidden cost.”

In his comparison of minimal estrus synchronization versus CIDR-based programs, the upfront numbers favor the simpler approach. Protocol costs averaged $4.05 per pregnancy for the estrus group, compared to $22.29 for the CIDR group. But the CIDR heifers were inseminated 12 days earlier and pregnant eight days sooner.

“The feed costs were $82 for the estrus group versus $50 for the CIDR group,” Fricke says. “So, we’re actually $16.66 more profitable per pregnancy by being more aggressive with the heifers.”

For Fricke, how the numbers are presented is just as important as the results.

“Farmers will look at the upfront cost,” he says. “We need to show them this is an investment, not just a cost.”

Make Every Heifer Count

As herds rely on fewer replacement heifers, the stakes for getting each one pregnant at the right time are higher than ever. Every day a heifer remains open adds feed costs and can delay her entry into the milking herd, making careful management more critical.

“When I look at dairies, the low-hanging fruit now is the heifer side,” Fricke says. “Heifers are kind of out of sight, out of mind, but heifers are important.”

Fricke emphasizes success in heifer reproduction is no longer just about hitting pregnancy targets. It’s about making the most of each heifer and ensuring the herd stays on track. By understanding how protocols, semen type and timing interact, and by viewing upfront breeding costs as an investment rather than an expense, farms can protect their replacement strategy and improve profitability across the herd.

Managing Heifer Mastitis: Targeting Risk Before Freshening

Fri, 05 Dec 2025 20:44:54 GMT

Heifer mastitis is often underestimated because it occurs before an animal has even entered the milking string, but the impacts are long-lasting. Subclinical infections at calving are linked to reduced production across the entire first lactation and often throughout the cow’s lifetime. For a class of animals that has yet to return any of their rearing investment, those losses are magnified.

“It’s been identified that an animal with an increased somatic cell count in the early parts of their first lactation, those animals produce less milk throughout that first lactation and many times have decreased milk production throughout their lifetime,” says Dr. Pamela Adkins of the University of Missouri. “So we are starting out of the gate not performing as well as we could, which obviously can be quite expensive.”

Based on data presented by Adkins, what’s becoming increasingly clear from recent research is heifer mastitis is not simply early-lactation mastitis in small cows. The timing, pathogen profile and management leverage points are all distinct. Because most new infections occur before the heifer ever enters the parlor, this disease demands a prevention strategy tailored to prepartum animals.

How is mastitis in heifers different from mastitis in older cows?

Across multiple studies, higher incidences of clinical mastitis have been observed in heifers during the first few days of lactation compared to older cows.

“It’s likely that those heifers acquire those infections prior to the onset of lactation,” Adkins explains. “Therefore, a lot of our focus potentially needs to be before lactation.”

This represents a shift from how we think about lactating cows.

Culture studies of heifers reinforce this: 29% to 75% of quarters can be culture-positive before calving and over 80% may be positive at first calving and in early lactation. In older cows, early lactation infection rates tend to be around 30%.

What kinds of bacteria are causing heifer mastitis?

The types of pathogens causing infection in heifers differs from those of adult cows. Heifers show a high prevalence of infection with non-aureus staphylococci (NAS), a lower prevalence of Staphylococcus aureus, and a higher prevalence of Streptococcus spp. compared to multiparous cows.

NAS are the most common isolates in heifers, especially Staphylococcus chromogenes. These are generally considered minor mastitis pathogens as they cause only a minor inflammatory response, but Adkins advises not ignoring these bacteria because they are highly prevalent.

Interestingly, NAS infection has been linked with lower incidence of clinical mastitis, and NAS inhibit the growth of pathogen bacteria in lab settings. These results suggest NAS could have a protective effect, but Adkins acknowledges there is a lot more in vitro and in vivo work to be done on this topic.

While not the largest contributor to heifer mastitis, S. aureus infection is still common. However, without the usual parlor-based transmission pathways, the question becomes how these heifers are becoming infected.

“In older cows, we consider the parlor the major concern of where the pathogen is coming from. We know [S. aureus] can be contagious, spread from cow to cow, and we think about that happening during milking time,” Adkins says. “Obviously that’s not happening yet in heifers. Therefore, we need to think of other factors that are important in heifers.”

Some older work looked into where S. aureus was found across seven dairies. Looking beyond milk and colostrum, isolates were found on the udder skin, muzzle, rectum and vagina. Adkins proposes these body sites were an important source of S. aureus infection for heifers. These infections also vary with geography and environment. The risk factors associated with an individual farm’s management and location need to be taken into consideration.

When are heifers most at risk of getting intramammary infections?

“In order to be able to prevent it, we need to know where we should focus so that we can implement prevention strategies at the right time points to help reduce infections,” Adkins says.

Work from her own lab sampled 304 quarters from 152 Holstein heifers. In comparing primigravid and nulligravid heifers, they found pregnant heifers had a higher incidence of positive quarters than non-pregnant heifers.

“Gestation and development of the [mammary] gland associated with pregnancy seem to be risk factors for increased prevalence of intramammary infections,” Adkins says.

These infections, in both pregnant and non-pregnant heifers, are significant because that animal is still growing and developing. Any infection could interrupt that process.

How do we diagnose heifer mastitis?

Without the usual diagnostic pathway of milk culture available, defining an intramammary infection in a heifer can be a bit tricky. In most young and early gestation heifers, there isn’t enough secretion present in the mammary gland to collect a meaningful sample. Collecting swabs from the teat or teat canal might be the best option at the moment, but it might not tell the whole story either.

“A lot of bacteria hang out just in the teat canal or the teat sphincter. They don’t necessarily go up into the gland,” Adkins explains. “If we just culture the end of the teat we can find bacteria that maybe aren’t causing a problem, which complicates our definitions [of infection].”

In research, needle based methods are used to bypass the teat end and go directly to the glandular tissue. However, these methods have not been validated in the field, and Adkins heavily advises against their use on farms.

Herd level factors you should review during your visit:

Overall herd udder health: Herds with lower overall somatic cell counts tend to have less heifer mastitis. Good management practices for lactating cows influence heifer health.
Early-life management: Heifers from farms with strong colostrum SOPs show lower mastitis rates, likely due to both enhanced immunity and overall better heifer oversight. Cross-suckling remains a concern due to teat end damage.
Fly control: It has been well documented that flies can carry mastitis pathogens and move directly between teat ends.
Contact with mature cows: Some research has linked prepartum commingling with increased mastitis risk, possibly due to both pathogen exposure and stress.
Time in calving area: Longer stays in heavily contaminated maternity environments significantly increase exposure risk.

Luckily, a lot of these factors come down to management decisions.

“Heifer mastitis is a major concern in many herds. Management is always a consideration for mastitis and a major consideration in heifers as well,” Adkins says. “Mammary health is related to herd level mammary health. So taking care of mastitis at all fronts is important, and considering environmental management strategies for your heifers is vital to try to reduce infections in these animals.”

Clinical Takeaways for Vets: Managing Heifer Mastitis

Think prepartum, not parlor. Most intramammary infections in heifers are acquired before calving; prevention efforts must target the rearing and prefresh periods.

Expect a different pathogen profile. NAS (especially S. chromogenes) and Streptococci dominate. S. aureus is present but less tied to parlors and more to skin, mucosal and environmental sources.

Use herd somatic cell count as a proxy. Herds with low bulk-tank and lactating-cow SCC typically have fewer heifer infections; poor overall udder health is a red flag to investigate replacements.

Audit early-life management. Verify colostrum SOPs, prevent cross-suckling, evaluate fly burden and assess cleanliness/turnover of prefresh and calving areas. These are high-yield levers.

Beware diagnostic pitfalls. Teat-end swabs overcall “infection”; needle sampling is research-only and not appropriate on-farm. Focus on first-test-day SCC and targeted cultures from clinical quarters postcalving.

Targeted protocols over blanket therapy. Emphasize environmental and management changes first. Use selective culture-based treatment strategies in fresh heifers rather than routine prepartum intramammary therapy.

U.S. Dairy Herd Continues to Grow: Fastest Pace in 17 Years

Mon, 25 Aug 2025 20:52:17 GMT

Last fall, after more than a year of low dairy cow cull rates, U.S. dairy producers started to rebuild the milk herd. So far this year, dairy producers have held cull rates low enough to add milk cows at the fastest rate since 2008, says Sarina Sharp, analyst with the Daily Dairy Report.

“While the heifer shortage has remained acute this year, today’s herd is the largest in four years, but it’s also growing older,” Sharp says. “To fill every stall, producers are holding on to cows for an extra lactation or keeping cows whose milk yields are lower than desired because not enough heifers exist to replace less-productive livestock.”

In late-September 2023, U.S. dairy producers began to rein in cull rates, sending fewer animals to packing plants. At first, the lighter slaughter volumes were not substantial enough to offset the ongoing heifer shortage, and the U.S. dairy herd declined. The herd continued to shrink until January 2024, but as producers continued to hold onto lower-end cows, the decline in U.S. milk cow numbers ended, and the national dairy herd began growing again last autumn, Sharp says.

“Now the trade is watching closely for any sign that cull rates are climbing, which would foster slower growth in milk cow counts” she says.

For the first time since March, USDA’s weekly slaughter volumes regularly topped 50,000 head in July, and in the last two weeks of the month, producers sent more cows to packing plants than they did a year earlier. At first glance, rising slaughter volumes appear to indicate the situation could be changing, but a deeper dive shows otherwise, according to Sharp.

“The increases in cull rates can easily be explained by seasonality, mathematics and weather,” she says. “First, cull rates typically jump in July following spring flush. And while U.S. dairy producers are now milking 146,000 more cows than a year ago, slaughter volumes can top last year’s very low counts without boosting culling percentages.”

Over the past two decades, she explains, dairy producers have typically culled about 32% of the milk cow herd each year. Last year, the cull rate dropped to 29.6%. This year, with 146,000 more cows, producers could continue to cull less than 30% of the herd and still send nearly 1,000 more cows to slaughter each week.

In addition, while slaughter in late July was unusually high in the Midwest, a derecho that slammed into the Central Plains was likely a major driver of the increase. USDA data showed that slaughter in the Midwest jumped 2,400 head above the prior year in the final week of July.

“Powerful winds damaged facilities and forced some producers to send cows to the packer while they repaired barns and milk parlors,” Sharp says. “Eventually, health and longevity will necessitate a return to historical cull rates, but for now, economics suggest slaughter volumes will remain near year-ago levels and expansion will continue, leading to strong milk production.”

Your Next Read:
Milk Production Soars: Record-Breaking Growth for Dairy Industry in Four Years

Dairy Heifer Shortage Builds the Case for Older Cows

Mon, 28 Jul 2025 15:44:29 GMT

It’s no secret that dairy heifers are in short supply, and their prices are high.

An early 2025 USDA-estimated inventory of just 3.914 million head of dairy heifers over 500 pounds marks the lowest population of dairy heifers in the U.S. since 1978. Meanwhile, the U.S. beef cattle herd is the smallest it has been in 64 years, ramping up incentives for dairies to produce more high-value beef-cross calves.

The financial upshot: today it is common for Holstein springers to fetch record-shattering values of $4,000 per head or more. That makes it challenging for dairies to grow or maintain herd size affordably. Or does it?

Surprisingly, dairy herd size has actually grown by about 114,000 head in the last year – to a current population of 9.410 million head -- through the recent heifer shortage and price-a-palooza. And May 2025 year-over-year milk production was up 1.56%.

That means stalls are being filled by the elder stateswomen of dairies. Higher-parity cows that may have been replaced by their first-lactation counterparts a few years ago are now likely being retained longer. And that’s largely for the best, according to Ryan Leiterman, DVM, Director of Technical Services at Crystal Creek Natural LLC , Spooner, Wis.

“Until recently, many dairies were milking 35% of their herd as first-lactation heifers, and some were even milking 50% heifers,” shared Leiterman. “These heifers are not even at their mature bodyweight yet, and they lack experience in the milking string.”

Leiterman said older cows can be an asset for the following reasons:

They’re better producers – Cows typically hit their peak milk production in their third or fourth lactation. Statistically second-calf cows out-pace first-calf heifers by about 10 lb./cow/day, and third-and-great lactation cows outproduce second-calf cows by an additional 10 lb./cow/day.
Milking them is easier – Multiparous cows, especially those in their fourth lactation and beyond, have more developed mammary tissue and better milk letdown.
They know the drill – Older cows are better adapted to the specific conditions of the farm, such as milking schedules and environmental stressors. While first-calf heifers require training and are often more challenging to milk and manage, older cows have the routines down.

Still, the veterinarian acknowledged that higher-parity cows do come with problems. To maintain an older cow population, Leiterman said a dairy needs to be on top of its nutrition and management game to prevent early herd removal or altered production due to ketosis, milk fever, mastitis, lameness, and poor reproductive efficiency.

But by caring fastidiously for those older cows, Leiterman said dairies can amortize the cost of rearing replacement heifers – which now may exceed $2,500 per head – over more years of productive life. They also may require fewer heifers, so they can capitalize on beef-cross calf sales, or sell their excess heifers at a healthy profit.

Or plain old internal herd growth, without the need to purchase replacements for herd expansion, is another potential benefit. In any case, it’s rarely wrong to strive to keep productive cows in the herd as long as possible.

“While a farm with good cow longevity is not guaranteed to be profitable, a farm with short longevity due to a high involuntary culling rate is not likely to be profitable,” Leiterman stated.

There’s a Lot of Info in That Little TSU

Tue, 29 Jul 2025 17:06:26 GMT

“The sky’s the limit if you have that sample,” says Jim Butcher, a Simmental seedstock producer from Lewistown, Mont.

He’s talking about all the things you can learn about the genetic potential of your cattle that is contained in a tissue sampling unit (TSU). The genomic information you get from each sample can, collectively and individually, help you more quickly move your herd’s genetic progress forward in an intentional, science-assisted direction.

There’s lots of info in that little vial.

(Allflex)

For commercial cow-calf producers, submitting the DNA sample in a TSU will return a scoresheet on each animal ‘s genetic merit for different indexes and specific traits, says Leoma Donsbach, owner and founder of Data Genie, LLC.

She calls herself a data accountant, helping customers attach the data on their operation to their record-keeping system. She says almost all her customers use TSUs to collect DNA and obtain genomic data.

Genomics are becoming more and more popular with commercial beef producers, she says.

“For replacement females, the ability to have a snapshot of that female’s genetic potential leads to increased confidence in keeping that heifer. You can say, ‘This heifer is more likely to be here until age six or seven by looking at her stayability metrics.’”

Say, for example, you’ve done your visual appraisal and picked 50 heifers as potential replacements, but you only need to keep 40. Visually, those heifers are very similar. But genetically, they could be very different, depending on what genes they received from their parents.

That’s where the TSUs and the genomic data they provide come in. First, test all 50 replacement candidates.

“Then breed them and find out which ones are bred,” she says. Even if everything went right, that still leaves some extras. “You can go back and use the genomic data to select the traits you want and/or use a maternal or terminal index to make those final decisions. You use it like comparing genomically enhanced EPDs when buying bulls.”

Beyond replacement selection, you can extrapolate the DNA data on your heifers when marketing your steers, she says. “On average, your steers will have similar genetics to your heifers. That information may add to their sale price.”

Then There Are The Bulls

Just like heifers, bulls can be full siblings and still be remarkably different in their genetic makeup.

“We’re great phenotype collectors of birth weights, weaning weights, all that,” Butcher says. “But you really don’t know what you have until you know what genes that particular animal picked up.”

When seedstock producers send in a TSU, they get back genomically enhanced EPDs. That, Butcher says, allows him to supply more accurate information about young bulls for his customers and help them make the best bull-buying decisions they can within their budget.

Indeed, not every bull is suited for every ranch. Studying the genomically enhanced EPDs gives you greater confidence in the true genetic potential of young bulls.

“You lessen the probabilities that you’re buying an animal that won’t help you move your program forward,” Butcher says.

Your Next Read: Building the Next Generation Cow Herd Using Genomic Testing

When Is the Best Time to Wean?

Thu, 24 Jul 2025 20:05:10 GMT

If conditions warrant, now might be the time to start thinking about weaning for spring calving herds. But weaning strategies are not one plan fits all, and what your neighbor does might not be the best decision for your herd.

The average suggested weaning age is 205 days. Four beef cattle extension specialists discuss the factors to consider if early weaning is the best option.

“Early weaning can be one of the most effective management strategies from both a grass/forage and cow nutrition standpoint,” says Jason Warner, Kansas State University extension cow-calf specialist.

According to Ron Lemenager, Purdue University beef specialist, the earliest recommended age for weaning a beef calf is between 60 days to 80 days, with 70 days being a common benchmark to ensure calves have a functioning rumen.

“When you wean at less than 70 days of age, the chances of having that calf turn out to be a little, potbellied orphan-looking calf goes up,” he says.

Warner adds weaning 60-to-90-day-old calves requires good, tight facilities to keep them in and feed bunks and watering troughs that the calves can reach.

Lemenager explains the decision to early wean is based on two things:

Feed resources: the kind of quality and quantity of feed.
Body condition of the cows.

John Hall, University of Idaho extension beef specialist, says there are two age ranges for early weaning. Very early weaning is weaning calves at 90 days prior to the breeding season. Producers can use this strategy to try and induce cycles in thin cows. He says calves weaned this early will require a unique management plan.

He describes early weaning as when the calf is between 150 days to 180 days of age.

“The nice thing about that 5-month-old calf is it’s only getting about 30% of its nutrition from the dam,” Hall explains. “So, making the switch when the calf is already used to eating a lot of forage is ideal.”

Megan Van Emon, Montana State University extension beef cattle specialist, encourages producers to plan to make sure the weaning process — no matter how the age of calf — goes smoothly.

“The earlier you can make the decision, the better,” she says. “Not only for the producer, but also for those calves to be prepared.”

Four Factors to Consider

The specialists share these points to aid in your early weaning decision:

Pasture and Forage Conditions
Drought is the primary trigger for early weaning. All four specialists encourage producers to assess pasture conditions, rainfall patterns and forage availability. If pastures are short and producers are concerned about overgrazing, then early weaning should be considered.

“In times of reduced forage availability — primarily drought — early weaning should be considered as a method to preserve the forage base by removing the forage demand from the calf and also reducing forage intake by the cow,” Warner says.

Van Emon explains the “take half, leave half” grazing principle becomes difficult when grass is only 3" to 4" tall, emphasizing the need to leave enough root reserves for future grazing.

Most of the research data suggests that for every two to two-and-a-half days that a calf is weaned, there is one more day of available forage for grazing for the dry cow.

“We can conservatively save or extend our forage resources by a third,” Lemenager explains. “Cow forage intake goes down and calf consumption of forage is eliminated in that grazing environment.”
Cow Body Condition
Hall says if cows are at a body condition score (BCS) 4 or lower by mid-summer, they’re in nutritional trouble and it’s likely their calves are not doing well in terms of growth rate either.

Early weaning removes the lactation demands, which will allow the cow to start regaining condition before winter. Lemenager also suggests early weaning can help reduce winter supplementation needs.

Lemenager and his family also have a cow herd in Indiana. They typically wean at about 6 months of age.

“That gives me an extra month of cows being able to pick up some body condition before the winter,” he explains.

Van Emon says research predicts for every two weeks earlier you wean, a cow will gain about a tenth of a body condition score.
Feed Resources Available for Newly Weaned Calves
It is important to have high-quality feed available for early weaned calves, as they require better nutrition for continued growth. Hall recommends producers work with a nutrition consultant or other extension specialist to create a nutrition plan for the newly weaned calves.
Facilities and Labor
Early weaning requires appropriate facilities with secure fencing and can require additional labor. Van Emon encourages producers to consider if they have the resources available to manage early weaning effectively.

Hall reminds producers the primary goal of early weaning is to maintain or improve cow condition and stretch limited forage supplies while supporting calf growth.

By carefully evaluating the factors suggested by the extension specialists and implementing proper management strategies, you can make early weaning a successful part of your operation when conditions warrant the strategy.

Your Next Read: Step-by-Step Weaning: How to Choose the Best Method

Fine-Tuning First-Lactation Performance with Smarter Data Management

Tue, 17 Jun 2025 15:31:38 GMT

It’s not easy to be the new kid in school. Or a first-lactation animal in a herd of older cows.

“Not only are first-lactation cows facing a new environment, a new ration and numerous physical changes that accompany giving birth, but they also have to adapt to a new social structure and daily routine, all of which is out of their control,” says Steve Pavelski, Nedap large herd specialist. “All of this adds up to stress and behavioral hurdles for these animals.”

To ease this transition, many producers are grouping first-lactation cows separately and using automated monitoring tools to better support them in the weeks after calving. These strategies are proving critical to long-term productivity.

First-lactation learning curve

How different are fresh heifers from mature cows? Research says: Quite a bit.

For example, first-lactation cows have different habits from older cows:^[1]

They are often more timid at the feed bunk due to their lower social status, especially during the week of calving, and eat less than other cows throughout the transition period.
Researchers also found that younger animals eat more slowly and more frequently than cows in their second lactation or higher.
Plus, first-lactation cows have different resting habits. They have shorter lying bouts, change their lying position more frequently and walk more than older animals.
When grouped with other first-lactation cows, they spend more time eating and lying down than when mixed with mature cows.

“This is a whole new scene for these animals,” says Pavelski. “We work with many herds that keep fresh heifers in smaller groups for the first two weeks to 30 days after calving. Sending a fresh heifer, especially one fewer than 10 days in milk, into a crowded pen often sets her up to struggle.”

Data-driven results

Research shows poor transition from pregnancy to lactation often results in the loss of 10-20 pounds of peak milk yield, which could equal 2,000-4,000 pounds of untapped milk yield.^[2]

However, dairies with access to accurate monitoring data have discovered that not only do they have a better handle on how all cows fare during transition, but also that moving healthy older cows out of transition groups faster results in improved performance of first-lactation cows, too.

“The Alta Cow Watch system is very effective for our day-to-day work and has made checking fresh cows more efficient,” says Ryan Nelson, Ohlde Family Farms, Linn, Kansas. “We’re able to catch something sooner so we can get her back to 100% and back to a good lactation.”

Better grouping, better gains

Monitoring system data fed into herd management software enables users to establish movement criteria. As trends emerge, reports indicate how well animals are adjusting to lactation demands and offer insight as to when cows should leave the fresh pen for lactation groups.

This strategy keeps cows that need more attention, such as first-lactation animals, in smaller groups while returning those meeting performance criteria to lactation groups and a higher plane of nutrition after a shorter fresh pen stay.

“The mature cows can move to the lactation group quickly, giving first-lactation heifers the space and time to adapt at their own pace,” Pavelski explains. “Monitoring data gives us a clear picture of how they’re adjusting and when interventions are needed.”

With actionable data in hand, dairies can make quicker, more accurate decisions. Instead of holding all cows in transition pens longer than necessary, producers can move animals based on performance, not guesswork or predetermined timeframes.

“The goal is to manage each cow as an individual, while letting the rest of the herd just be cows,” Pavelski concludes.

Visit nedap-livestockmanagement.com to learn more.

About Nedap

Nedap creates Technology for Life: technological solutions that help people become more successful and happier in their professional lives. Nedap’s Digital Twin Technology bridges the physical and digital worlds, offering real-time insights and automation in Livestock, Healthcare, Retail, and Security. Nedap Livestock helps farmers to optimize the performance and well-being of individual cows while minimizing workload and resources. This way, Nedap improves life on the farm for both people and animals, helping to reduce the environmental footprint of dairies worldwide. Nedap N.V. has a workforce of over 1,000 employees and operates on a global scale. The company was founded in 1929 and has been listed on Euronext Amsterdam since 1947. Its headquarters are located in Groenlo, The Netherlands.

Creep Feeding: Will it Pay Off?

Thu, 05 Jun 2025 20:24:45 GMT

To creep feed or not to creep feed. That is the question many ranchers ask themselves during the summer. Feed of any kind is always an added input, so what should ranchers consider to ensure this practice is profitable? Mark Johnson, Oklahoma State University professor of animal and food sciences, shares several creep feeding pointers in the recent episode of the Casual Cattle Conversations podcast .

Before you can determine if a practice is profitable, you must first ask yourself the purpose of the practice.

“The bottom line of creep feeding is to put additional weight on calves through additional nutritional resources that only the calves have access to,” Johnson says.

This is done by providing feed to calves that their mothers do not have access to.

A secondary benefit to creep feeding is that it acts as a pre-weaning aid. Calves become used to eating out of a feeder, which will reduce stress and offer some familiarity in diet and routine once weaning comes around.

Creep feeding doesn’t come without its challenges either. The practice requires additional equipment to provide the feed and producers need to be cognizant of reducing spoilage, keeping feed fresh and that rodents can help themselves to the ration as well.

Once producers weigh the pros and cons, it’s time to pencil out the cost of gain.

“Historically, when we looked at research data we did not find it cost effective when comparing cost of gain to the value of a weaned calf. Now, the current cattle market we are in is a game changer,” Johnson says.

Creep feeding is a practice he pencils out for his own cattle each year to determine if it financially makes sense.

“We were putting gain on for far less than the gain was worth and were simultaneously experiencing a drought. It penciled out for us last year,” he says.

One consideration sometimes forgotten about is that not all added weight on calves is created equally.

“In some cases that additional weight results in over conditioning, which results in a discount in the marketplace,” Johnson explains.

If creep feeding does pencil out for ranchers, they should consider the quality of their grass and age of their calves when deciding the ideal protein and energy levels of the feed. The length of the feeding period should also be factored.

Johnson says, “You can creep feed one to two months prior to weaning and can see adequate benefit compared to feeding for extended periods.”

If creep feeding doesn’t look like a profitable practice but producers still want to provide calves with feed that their mothers don’t have access to, creep grazing is another option to consider.

“If there is the possibility to have an area of pasture that only calves have access to, you can also get an effective cost of gain,” Johnson says.

Remember that only you can determine what is profitable for your operation and that input and cattle prices vary from year to year.

“One of the things I love about the beef industry is that we raise cattle in a variety of production environments and nothing is a one-size-fits-all practice,” Johnson says. “So, I encourage people to put pen and paper to their practices to see what works for them.”

Your next read: Protecting Your Profits With Price Insurance

National Mastitis Council Plans Regional Meeting, Registration Now Open

Thu, 15 May 2025 14:19:10 GMT

The Global Milk Quality Organization invites you to attend the 2025 National Mastitis Council (NMC) Regional Meeting, set for July 22-24, in Rochester, N.Y., at the Hyatt Regency Rochester.

With a theme of “Clearing Hurdles to Improve Milk Quality,” this event will bring together dairy producers, veterinarians, researchers and industry professionals for a collaborative exchange of knowledge and innovative practices to tackle key challenges in milk quality and udder health.

Find details about the NMC Regional Meeting at: https://www.nmconline.org/2025-regional-meeting-agenda . To register for this event, go to: https://bit.ly/NMC2025Regional .

As the dairy industry continues to evolve, so do the obstacles that hinder optimal milk quality and production, and animal welfare. The NMC Regional Meeting will feature expert-led sessions on emerging mastitis pathogens, on-farm milk quality strategies, antimicrobial stewardship and technologies for monitoring herd health.

“Our goal is to help dairy professionals identify and overcome the barriers that hinder milk quality,” said Rick Watters, an NMC board member and regional meeting co-chair. “By bringing together some of the brightest minds and most practical tools in the field, we aim to drive significant progress for enhancing udder health.”

The 2025 NMC Regional Meeting includes short courses, general sessions, panel discussions, dairy farm tours and networking opportunities designed to foster practical learning and actionable solutions.

Short Course topics and presenters* to include:
Troubleshooting Bacteria Counts in Conventional Milking Systems: Paul Virkler, Quality Milk Production Services, and Rick Watters, AgroChem

Milking System Design & Analysis: Roger Thomson, MQ-IQ Consulting and Michigan State University

Mastitis Microbes I: Let’s Figure Out the Bugs Behind the Battle: Quinn Kolar and Michael Zurakowski, Cornell University

The Milking Routine: Lisa Ford, Cayuga Marketing, Kaitlyn Lutz, Cornell University, and Francisco Mendoza Gomez, Newmont Farms (taught in Spanish)

Troubleshooting Bacteria Counts in Automated Milking Systems: Kira Andersen, Lely, and Guy Séguin, Dairy Farmers of Ontario

Milking System Vacuum and Airflow Testing: Roger Thomson, MQ-IQ Consulting and Michigan State University (hands-on training using the “Teaching Parlor”)

Judicious Use of Antimicrobials: Matt Chuff and Tracy Potter, Perry Veterinary Clinic

The ABCs of Milking Machines: Operation, Cleaning and Inspection: Carolina Pinzon, University of Wisconsin, and Dario Roma, DCR Consulting (taught in Spanish)

Identification of Mastitis-causing Organisms Using On-farm Methods: Quinn Kolar and Michael Zurakowski, Cornell University

Wash System Analysis: Roger Thomson, MQ-IQ Consulting and Michigan State University, and Rick Watters, AgroChem

General Session topics and presenters* to include:
Bedding Management: How to Interpret Bedding Bacterial Counts – Felipe Peña Mosca, Cornell University

Beyond Cell Count: Non-traditional Measures of Milk Quality – Nicole Martin, Cornell University

Milk Quality Standards: Beyond SCC and SPC – Kaitlyn Briggs, fairlife

Capitalizing on Sensor Technology – Julio Giordano, Cornell University

Using Artificial Intelligence to Interpret Data Silos – Elsa Vasseur, McGill University

How to Use Camera Technology Without Infringing on Employees’ Privacy Rights

Panel Discussion: How Dairy Farms are Using Artificial Intelligence and Camera Technology

*Topics and presenters subject to change.

Plus, tour some of New York’s finest dairy farms on July 24. The tour features Reyncrest Farms, Corfu, N.Y.; Bonna Terra Farms, Bloomfield, N.Y.; and Rudgers Registered Jerseys, Attica, N.Y.

Additionally, you won’t want to miss NMC’s Taste of New York – set for the evening of July 22. Taste some of the Empire State’s finest cheeses, wines and beers. And, participate in NMC’s first-ever chocolate milk tasting contest.

To make your hotel reservation at the Hyatt Regency Rochester, go to: https://bit.ly/NMCregionalmeetingHotel . Book your hotel room by June 30 in the NMC room block to take advantage of the discounted rate of $129 per night (not including taxes and fees).

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Cow Herd Scorecard: Evaluating Performance Post Calving

Wed, 14 May 2025 21:59:31 GMT

Tracking performance and evaluating herd success is a year-round process. Similar to tracking athletes, consider developing a scorecard to monitor your herd.

Understanding how your herd is performing throughout the year is important when considering management, nutrition and culling decisions.

For spring-calving herds, now is the time to evaluate and review calving success and failures.

“This is a good time of year to review your records, and if the numbers aren’t where you want them to be, you can make management adjustments under the guidance of your veterinarian, nutritionist or another adviser,” says Jason Warner, Kansas State University cow-calf Extension specialist. Warner was a guest during a recent K-State Beef Cattle Institute Podcast .

A herd’s postcalving scorecard should include:

pregnancy percentages
death loss
calving ease/calving complications – prolapse or retained placenta
udder scores
body condition score
mothering ability and disposition
calving interval

Two areas Warner tells producers to focus on are the number of live calves born compared to the number of cows exposed to bulls at the start of the breeding season; and the number of cows that became pregnant early in the breeding season.

A top priority for Bob Larson, K-State veterinarian, is to have calves born early in the calving season.

“The goal is to have 65% of the calves born in the first 21 days, and 85% to 90% of the calves born within the first 42 days of the season,” Larson say. “If that happens, I know that the cows were in good body condition at the start of the breeding season and the bulls were fertile.”

Larson references USDA’s National Animal Health Monitoring Service (NAHMS) for national averages on abortion and calf death loss.

“The national average is between 1% to 2% for calf death loss and that will vary from year to year within the same operation,” Larson said. “If the producer is calving out a high percentage of heifers, that can influence the calf death loss percentage.”

Scorecard Prep
Ron Lemenager, Purdue professor and beef Extension specialist, suggests producers consider creating a spreadsheet to calculate important percentages, prior to filling out their postcalving scorecard.

He encourages producers record and monitor these numbers each calving season:

Number of cows exposed
Number of cows pregnant
Number of cows pregnant / Number of cows exposed = % Pregnant
Number of pregnant cows kept to calve
Number of cows that calved
Number of cows that calved / Number of pregnant cows kept to calve = % Calving
Number of Live Calves
Number of Live Calves /Number of cows that calved = % live calves born
Number of live calves after one month
Number of difficult or assisted birth (dystocia, prolapse)
Number of cows with bad udders
Number of cows BCS 5 or 6
Number of cows with poor disposition and poor mothering ability
Number of cows that calved in the first 21 days
Number of cows that calved in the second 21 days
Number of cows that calved in the third 21 days
Number of cows that calved after 63 days

Lemenager explains using the spreadsheet to calculate the percentages can help producers identify specific problem areas in their calving and breeding processes and allows them to troubleshoot their herd’s breeding performance.

“Tracking herd performance allows producers to zero in on their problems and determine what issues are really facing the herd,” he summarizes.

Understanding the challenges facing a cow herd can help producers determine what nutrition or management strategies can be used to improve their herd’s postcalving scorecard in future years.

Your Next Read: Spring Cattle Processing Tips to Enhance Herd Health and Diminish Stress

BVDV: A Threat The Beef Industry Can’t Afford to Ignore

Tue, 06 May 2025 19:43:01 GMT

Some veterinarians and producers think of bovine viral diarrhea virus (BVDV) in narrow terms – as the virus that causes persistently infected (PI) cattle. And while that perspective is correct, Dr. Thomas Passler, DVM, PhD, says there are broader implications for BVDV and its impact on cattle and some other animal species worldwide.

“(BVDV) has evolved over the years and is not a single virus or just a diarrhea-causing problem. Today it’s made up of three related viruses and 19 subtypes that cause similar diseases,” explains Passler, the Jack Rash professor of internal medicine for food animal medicine at the Auburn University College of Veterinary Medicine.

“It’s a sneaky, insidious disease,” he adds.

Passler estimates 0.5% of U.S. cattle are persistently infected by BVDV. Of that percentage, only a small number of those animals become PI cattle – a result of infection caused during fetal development between 40 and 125 days of gestation and which persists during the animal’s entire life.

The PI problem differs from transient infection (TI), which occurs when an animal becomes infected after birth. A TI animal is infected temporarily, but during that time is capable of shedding the virus and transmitting it to other herd members or pen mates.

Multiple Health Issues And Losses Across Species
BVDV-positive animals, especially PI cattle, significantly impact U.S. herds by causing immunosuppression, weakening immune systems and making herd mates more susceptible to other infections. Passler says that immunosuppression often manifests as increased calf death losses from diseases such as scours and pneumonia, as well as poor weaning weights.

Passler adds that he has seen similar problems from BVDV in other animal species, including hogs, white-tailed deer, alpacas and goats.

BVDV is one of the costliest bovine diseases for beef producers and dairy producers, as well. Losses average between $15 to $88 per head, conservatively, according to Indexx Laboratories , citing older data from 2002 and 2008.^1-3

Despite the associated costs, a 2017 National Animal Health Monitoring System (NAHMS) study of 75 U.S. cow-calf producers (the summary was released in 2023) reported only 57.5% of participating producers said they knew some basics or were fairly knowledgeable about BVDV. In addition, 26.9% of producers said they “recognized the name but not much else,” and 15.3% of respondents said they had never heard of it (see Figures 1 and 2).

Furthermore, most BVDV infection problems in cattle herds go unnoticed since 70% to 90% of BVD infections are subclinical (do not result in observable disease), according to the Washington Animal Disease Diagnostic Laboratory .

The Beef 2017 study was conducted in 24 of the nation’s major cow-calf States. In 2017, operations in these states accounted for 86.6 percent of the U.S. beef cow inventory and 78.9 percent of all U.S. operations with beef cows.

(NAHMS)

Only 24.4% of the cattlemen surveyed said they are “fairly knowledgeable” about BVDV.

(NAHMS)

Contributing Factors To PI Cattle
Direct contact with infected animals and with contaminated fomites (water buckets, calf feeders, feed bunks, IV equipment, etc.) are common ways BVDV gains a foothold in a herd.

One risk factor that often flies under the radar is the use of intranasal vaccines that do not address BVD viruses, reports Dr. Dan Thomson, PAC veterinarian and Iowa State University professor emeritus.

“We’re using a lot more intranasal vaccinations, thinking that we’re covering for BVDV when we’re actually not,” says Thomson, who spoke with Passler recently on an episode of DocTalk.

It’s a perspective Passler says he agrees with. “We see mucosal disease in the clinic – something we shouldn’t be seeing at all – and often from herds that vaccinate,” he adds.

Intranasal vaccines for respiratory disease do not currently contain BVDV Type 1 & 2, so a separate injectable BVDV vaccine is required, according to Craig A. Payne, DVM, and Celeste Morris, DVM, respectively, at the University of Missouri. Payne and Morris discuss this contributing factor further in their online article, Vaccination Program for a Cow-Calf Operation .

Key Into The Correct Timing To Test Calves
Payne and Morris recommend that “because PI animals are so detrimental, the standard recommendation in herds where BVDV is suspected is to implement a testing strategy and remove any PI animals detected. Vaccination alone cannot counter the effects PI animals can have.”

Specific to calves, Passler says it’s important for veterinarians to let producers know the timing of the testing can impact results – maternal antibodies can skew the results.

“Either test the calf as soon as it hits the ground, before it can nurse, or wait at least a week or [even up to] a month later,” he advises.

He encourages practitioners to talk with cow-calf producers about testing calves to identify BVDV.

“A lot of people don’t test until those animals are stockers or going to the feedlot, and that’s too late,” Passler says. “We want producers to test earlier so they can remove PI cattle sooner.”

Evaluate Vaccines And Protocols
There are two main types of vaccines for BVDV: modified-live (attenuated) and killed (inactivated).

The most significant value for beef producers in using a vaccine that addresses BVDV is being able to protect a dam’s fetus, Passler says. But no vaccine is perfect, he adds, noting producers must also be diligent with their management practices.

“What we have seen here in the clinic is that even in well-vaccinated herds – those we know use killed vaccines religiously – they still get PI cattle if they’re not careful about biosecurity,” he says. “These might be herds that religiously vaccinate, but they still go to the stockyards and buy replacements or take some other sort of risk.”

As for vaccine use protocols, Passler says his review of other researchers’ work indicates it’s best if producers use at least one modified live vaccine and then an inactive (killed) vaccine to vaccinate cows and heifers.

“I’d probably [vaccinate] two cycles and well before gestation, because vaccine seems to reduce fertility a little bit,” he says. “Some researchers say 42 days in advance [of gestation] is a good number to use”

Another practice Passler advises is using products from more than one manufacturer. “Different manufacturers use different vaccine strain viruses, so you might increase endogenic exposure,” he explains.

Thomson supports that recommendation. “We do that when we deworm, we do it with how we treat bacteria, so why wouldn’t we do that to prevent BVDV? That’s great advice,” he says.

Your next read: Can Oxytocin Boost Colostrum?

References

1. Bartlett B, Grooms D. BVD-PI eradication: unintended consequences. Michigan Dairy Review. 2008;13(3).

2. Chi J, VanLeeuwen JA, Weersink A, Keefe GP. Direct production losses and treatment costs from bovine viral diarrhoea virus, bovine leukosis virus, Mycobacterium avium subspecies paratuberculosis, and Neospora caninum. Prev Vet Med. 2002;55(2):137–153. doi:10.1016/s0167-5877(02)00094-6

3. Ridpath J. Why BVD is a tough problem. Hoard’s Dairyman. 2002;147:697.

More Than Annoyance: Flies Can Impact Health and Profits

Tue, 06 May 2025 20:15:55 GMT

With fly season approaching, now is the time to evaluate and refine your fly management plan for 2025.

“If your 2024 control efforts underperformed, consider adjusting your approach,” says David Boxler, Nebraska Extension livestock entomologist. “The best control method will depend on several factors including efficacy, cost, convenience and your current herd management practices.”

He also reminds producers that horn flies can migrate from neighboring untreated herds, masking the effectiveness of your efforts and increasing fly pressure. For this reason, Boxer recommends a comprehensive, integrated fly control.

The horn fly is one of the most damaging pests of pasture and rangeland cattle across the U.S., Boxler says in a recent “ UNL Beef Watch .”

“Adult horn flies are blood-feeding insects that take an average of 30 blood meals per day,” he says. “Their populations can build rapidly and often exceed the Economic Injury Level defined as 200 flies per animal. Once fly numbers surpass this threshold, cattle experience reduced weight gain and milk production due to fly-induced stress and altered grazing behavior.”

Observing your cattle during summer months is key to detecting fly pressure. Boxler asks, “Are they constantly tossing their heads, swishing their tails or twitching their skin?”

These signs of fly irritation indicate a more effective control strategy might be needed.

“If you are seeing flies, ticks, lice or insect damage to your cattle herd, we know there is an economic impact; however, that impact can become far greater than production or weight gain loss alone,” says Ashby Green, DVM, Neogen senior technical services veterinarian. “Insect pressure affects grazing patterns of cattle, it affects their comfort and it can lead to health issues. Some of those health issues can be definite, such as anaplasmosis.”

The vectors responsible for spreading anaplasmosis include horse flies, stable flies and ticks. This condition has been reported in most states across the U.S., while the disease has been recognized as endemic throughout the South and several Midwestern and Western states.

“With horn flies, we’re looking at mastitis risk, so that’s going to impact both dairy cattle and also our cow-calf operations,” says Jonathan Cammack, Oklahoma State University assistant professor and state extension specialist. “A lot of times, horn flies will feed on the udders of the animals, and they transfer the Staphylococcus aureus bacteria because they land on the manure, then they go back to the animal to feed and bring those bacteria with them.”

Several other conditions are propagated by flies or ticks, including pinkeye, which can be spread by face flies and causes inflammation and ulceration of the eyes. Pinkeye-affected calves are, on average, 35 lb. to 40 lb. lighter at weaning compared to healthy calves, according to a University of Kentucky report.

Cammack says that due to flies, “We’re looking at probably $6 billion in losses annually to U.S. cattle production, and that encompasses everything from actual loss in production due to decreased weight gain or decreased milk production, veterinary needs associated with treatment of cattle with exposure to pathogens from some of these insects, and then also the control measures associated with managing those individual fly species.”

Ticks present economic risks as well. Cammack says that during a 100-day growing period producers can see a decrease in total weight gain in calves by about 20 lb. For stockers, over that same 100-day period during the summer months, they can experience a decrease in weight gain by about 60 lb.

“With what current prices are, 60 lb. could translate to a significant amount of money returned when we’re talking about the few dollars that it might cost for some tick control,” he says.

(Neogen)

Controlling flies and insects: Tips to implement
Now is the time to take steps to control flies and ticks, as populations emerge with the warmer weather.

In “ Stopping Flies in 2025: Tips to Battle These Economic Pests ,” Cassandra Olds, Kansas State University Extension entomologist, shares four steps to controlling flies

Know what flies you’re dealing with.
Reduce populations.
Eliminate breeding grounds.
Consider chemical control options.

Similar to Olds, Green recommends using a multi-pronged approach to insect control. Fly tags, feed-through insect growth regulator (IGR) products, pour-ons, back rubbers and dust bags can help diminish the population. A pour-on with an IGR destroys the larval development in flies and greatly reduces the fly population. For ultimate control using a pour-on, look to a unique combination of actives within one solution that includes an IGR, an adulticide, and a synergist that supplies relief to cattle from infestations and provides producers with a reliable solution that helps minimize handling, time and labor costs.

“Both back rubbers and dust bags can be highly effective if managed correctly. Keep in mind, when these are put out to withstand the elements, including moisture and rain, it’s key to keep the dust fresh or the oil recharged in your back rubbers. Otherwise, they will diminish in their ability to control flies quickly,” Green advises.

Cammack stresses the importance of accurate dosing by the individual animal’s weight and following label guidelines.

To best control flies and insects on cattle operations, “the easy and effective way is the best way,” Green summarizes. “It’s up to you and with the help of your veterinarian to help create that combination.”

Your Next Read: Functional Facilities Reduce Stress and Boost Efficiency

Streamline Spring Cattle Processing with These 3 Stress-Reducing Steps

Thu, 01 May 2025 15:46:11 GMT

Reducing stress during livestock handling can increase productivity, maintain or improve meat quality, reduce sickness and enhance animal welfare. Implementing low-stress handling techniques when working with cattle is important to reducing stress.

As producers prepare for spring processing, Beth McIlquham, University of Wisconsin-Madison regional livestock educator, encourages producers to consider these low-stress handling strategies.

“While temperament in cattle is moderately heritable, environment does play a role and even cattle that are less docile will benefit from low-stress handling methods,” Mcllquham says. “A good handler can help reduce fear in an animal, which is the primary driver of negative consequences associated with handling stress.”

Even if the animal is not experiencing any pain, fear can still cause physical responses in the body, such as high cortisol levels. These responses can ultimately lead to increased susceptibility to illness, lower meat quality and overall lower performance.

Mcllquham says one negative handling experiences can affect future handling situations.

Identifying stress through body language
Cattle in a state of fear or under stress can be identified through their body language. Obvious signs of fear in cattle are running, kicking, vocalizing and aggressive behaviors toward handlers. Subtle signs of fear are heavy breathing and showing the whites of their eyes. Stressed cattle can cause serious injury to themselves and humans. Relaxed cattle are quiet and walk or trot calmly. When low-stress handling techniques are used, the risk of injury is lowered.

“Besides increasing performance and lowering sickness and injury rates, consumers have indicated that they care that their food is humanely raised,” McIlquham explains. “Implementing low-stress handling is a great place to start and comes with many other benefits. Although it may sound like a daunting task, utilizing low-stress handling techniques can be done in smaller steps.”

Step 1: Put away the electric prod
“Our first step is to put away the electric prod,” she says. “To decrease use, place electric prods away from where you’re handling cattle but still be accessible in an emergency. This way, instead of instinctively reaching for it, the inconvenience of going to grab it can decrease electric prod use.”

Step 2: Understand cattle’s natural instincts
“We should utilize these instincts to work for us instead of against us,” she says. “The fact that cattle are prey animals drives a lot of their behaviors.”

Cattle are herd animals and like to be in groups. When moving them, keeping cattle in small groups (two to five head) can help keep them calmer and easier to handle. Additionally, cattle want to see you. Humans are naturally predators, and because cattle are prey animals, their instinct is to be able to keep handlers in sight.

Cattle want to go toward lighted areas and will resist going into darker areas. It is easier to see any potential threats in areas that are light. Keep in mind shadows can reduce cattle flow through an area.

Step 3: Study and use cattle’s natural flight zone
Good handlers study and use cattle’s flight zone and point of balance, McIlquham explains.

Two concepts are illustrated in Figure 1.

Figure 1. Flight Zone and Point of Balance

(Beef Quality Assurance Cattle Care & Handling Guides)

Walking into the flight zone makes the animal move away from the handler. Stepping out of the flight zone will take pressure off and remove the animal’s desire to continue to move away. Note that the size of flight zones varies between animals. The point of balance allows handlers to move the animal forward or backward. Stepping into the flight zone in front of the point of balance will make the animal move backward. Stepping into the flight zone behind the point of balance will drive the animal forward.

Keep in mind cattle have a blind spot directly behind them. If you approach the animal in the blind spot, they could get spooked. Walking in a zigzag pattern behind cattle helps let them know you are there.

Extra tip: Taking breaks
Calm cattle are easier to move than stressed cattle. Fearful cattle are more reactive, more easily injured, and more likely to engage in aggressive behaviors. If a handling situation does get intense, take a little break and release pressure on the cattle.

“Even taking a brief break can help both the animal and handler calm down and come back to the situation in a more positive light,” Mcllquham summarizes.

Your next read: Effective Needle and Syringe Strategies to Ensure Spring Processing Success

The Effects of Heat Stress on Dairy Cattle Development, Health and Performance

Tue, 22 Apr 2025 22:08:39 GMT

It is not breaking news that yearly temperatures on Earth have been consistently rising. Indeed, data released from NASA’s Goddard Institute for Space Studies – GISS show that the global land-ocean temperature index has consistently increased after the 1900s (see Figure 1 below).

Regardless of the many factors that have been tied to the increase in global temperature (some that were addressed in previous WSU VetMed Extension Articles ), it is evident that the agriculture is affected by such changes, including the dairy industry. With increased global temperatures, the occurrence of heat stress (a condition that occurs when the body is exposed to excessive heat, leading to an inability to regulate body temperature effectively) and its associated detrimental impacts are more likely to be observed particularly in dairy cattle.

A recent study projected the decadal increases in average heat stress frequencies by 2100, and revealed that the majority of the U.S. regions will have at least 6 to 8 additional days under heat stress/decade until 2100 ( Gunn et al., 2019 ; Figure 2).

Because of the expected differences in climate, it is important that dairy industry stakeholders work together to further 1) understand the complexity and underlying mechanisms of heat stress impacts, and 2) develop alternative strategies to mitigate the detrimental impacts of heat stress.

With that in mind, this article focuses on reviewing some of the key aspects related to heat stress impacts on cattle development, health and performance, industry economics, and mitigating strategies.

Historically, the temperature-humidity index (THI) has been the mechanism used to determine when dairy cows are heat stressed. Although there is some variation on THI cut-offs the consensus was established as a THI between 68 and 70 ( Zimbelman et al., 2009 ; Chen et al., 2024 ). Guinn et al. ( 2019 ) described the differences in mean THI between summer and winter months in the U.S. for the last 10 years (69.5 vs. 39.3, respectively), highlighting that without any heat stress abatement strategies U.S. dairy cows could be under heat stress conditions for most of the summer months.

In fact, the same study revealed differences in productive and reproductive performance between summer and winter, illustrated by reduced milk production and pregnancy rates in summer compared with winter months. Similar results were also reported by other authors, including lowered pregnancy rates in warmer months compared with colder months of the year ( Hansen, 2009 ). Both Tao et al. ( 2020 ) and Ouellet et al. ( 2020 ) depicted the detrimental impacts of heat stress on milk production and dry-matter intake (Figures 3 and 4).

Other studies have demonstrated the effects of heat stress (or contrast between warmer vs. cooler months) on the occurrence of diseases, culling, and cow welfare. For instance, cows that calved in warmer months were observed to have greater odds of retained fetal membrane (Odds Ratio = 1.6), subclinical ketosis (Odds Ratio = 2.3), displaced abomasum (Odds Ratio = 1.8), and mastitis (Odds Ratio = 1.1) as compared with cows that calved in cooler months ( Pinedo et al., 2020 ).

Al-Qaisi et al. ( 2020 ) observed a greater somatic cell count in milk from cows exposed to heat stress conditions as compared with cows exposed to thermoneutral conditions, and cows that calved in the summer were more likely develop metritis as compared to cows that calved in cooler months ( Molinari et al., 2022 ). Furthermore, Vitali et al. ( 2015 ) reported higher mortality of cattle during heat wave periods compared to subsequent periods, and an association of mortality and heat wave duration (Figure 5). Heat stress conditions have also been associated with welfare issues in dairy cattle, as cows under heat stress conditions remain in a standing position for greater periods of time (possibly contributing to lameness issues) and have greater blood cortisol levels than cows under thermoneutral conditions ( Cook et al., 2007 ; Allen et al., 2015 ; Al-Qaisi et al., 2020 ).

Considering the effects of heat stress on cattle performance, mortality, and welfare, it is not a surprise that economic losses occur. Specifically, data published in 2003 estimated that heat stress conditions cause up to $2.3 billion/year in economic losses to livestock production ($2.9 billion in 2024 considering inflation). Under heat stress abatement strategies, the economic losses drop down to $1.7 billion/year and the dairy industry represents over 50% of the costs ($897 million; St-Pierre et al., 2003 ).

A component to heat stress in dairy cattle that has received a lot of attention is the “in utero” heat stress on dairy calves. Recent studies highlighted the carryover effects of late gestational heat stress on the progeny, illustrated by lowered birth weight (-4.6 kg), lowered weaning weight (-7.1 kg), and reduced longevity ( Ouellet et al., 2020 ). Moreover, the occurrence of heat stress during the dry period is also associated with differences in offspring mammary gland structure ( Dado-Senn et al., 2019 ), adrenal gland development ( Guadagnin et al., 2024 ), behavior ( Laporta et al., 2017 ), and hormonal/metabolic biomarkers ( Guo et al., 2016 ).

Lastly, combined studies have shown the legacy effect of heat stress on offspring, as lactational performance of such offspring is also different compared to offspring generated by dams under thermoneutral conditions ( Ouellet et al., 2020 ; Figure 6).

The research findings related to the legacy effect of heat stress on offspring add another layer of importance to the topic, and suggest that the detrimental effects and economic losses previously described are potentially underestimated.

Although the complex mechanisms that underlie the detrimental effects of heat stress on lactating dairy cows are not yet fully elucidated, studies have demonstrated biological changes associated with heat stress. For instance, lipopolysaccharide-induced accumulation of IL-1β, IL-10, and MIP-1α was greater in blood collected from postpartum cows that were under prepartum heat stress conditions as compared with control cows,implying that prepartum heat stress has carry-over effects on postpartum innate immunity, which may contribute to the increased incidence of uterine disease observed in cows exposed to prepartum heat stress ( Molinari et al., 2023 ).

Other studies have depicted differences in gut, ovary, muscle, and metabolism morphology/function associated with heat stress, which could be tied to the occurrence of subsequent diseases, animal performance, reproductive performance, and mortality ( Baumgard and Rhoads Jr, 2013 ; Fernandez et al., 2015 ; Hale et al., 2017 ; Ross et al., 2017 ; Fausnacht et al., 2020 ; Mayorga et al., 2020 ; Tang et al., 2022 ; Roths et al., 2023 ). Last but certainly not least, and certainly not depicting the entirety of the mechanisms of heat stress associated with cow performance, cows under heat stress conditions have reduced feed intake ( Rhoads et al., 2009 ) and reduced energy substrate adaptability in skeletal muscle, possibly contributing to reduced performance ( Ellett et al., 2025 ).

Given the detrimental impacts of heat stress on cattle performance, health, and welfare, it is important to consider the region-specific variations in climate and implement heat abatement strategies as needed. There are a variety of heat abatement strategies available for dairy calves, heifers, and cows that can be implemented in dairy operations. Multiple studies have tested the effects of different strategies for heat abatement in calves.

For instance, Dado-Senn et al. ( 2020 ) reported a positive association between postnatal heat stress abatement and thermoregulatory responses, feed intake, and health in dairy calves. Montevecchio et al. ( 2022 ) reported a positive relationship between pre-weaning heat stress abatement and lying behavior and healing time (related to disbudding) in dairy calves. The same group also reported positive welfare-related responses and greater wither-height for calves given heat abatement strategies as compared to calves under a simple plywood hutch ( Montevecchio et al., 2022 ).

Benefits for heat abatement in heifers and cows were also reported. For instance, the use of shade from a freestall barn, water soakers, and fans were associated with positive effects on heifer thermoregulation and productivity as compared with heifers kept under freestall shade only ( Davidson et al., 2021 ). Gunn et al. ( 2019 ) described the milk production losses (per cow/year) according to different heat abatement strategies, ranging from minimal (open barn or shading) to intense (air conditioning).

Aside from structural tools to improve heat abatement for dairy cattle, other studies have reported varying results associated with nutritional tools to ameliorate the impacts of heat stress in dairy cows, including chromium supplementation ( Soltan, 2010 ), Saccharomyces cerevisiae supplementation ( Al-Qaisi et al., 2020 ), choline ( Holdorf and White, 2020 ), and other components ( Fabris et al., 2017 ).

The potential of other strategies for heat abatement have been described; for example, a research group from the University of Florida reported that the SLICK haplotype confers thermotolerance in intensively managed lactating Holstein cows ( Dikmen et al., 2014 ). In that study, the authors revealed that cows carrying the SLICK haplotype had lowered rectal temperature and respiration rate across most times of the day compared with cows not carrying the SLICK haplotype.

Although several aspects associated with the SLICK haplotype have not been explored, a recent study reported that SLICK Holstein cows in Puerto Rico exhibited lower body temperatures, greater voluntary solar radiation exposure, enhanced blood supply to the mammary gland, and alterations in genes and metabolites involved in arachidonic acid metabolism at the mammary gland and blood plasma ( Contreras-Correa et al., 2024 ).

Figure 1

(The Author)

Figure 1. Global land-ocean temperature index ( NASA’s Goddard Institute for Space Studies – GISS ).

(The Author)

Figure 2. Projected decadal increases in average annual Heat Stress Frequency between 2000 to 2100 ( Adapted from Gunn et al., 2019 ).

Average Daily THI

(The Author)

Figure 3. Correlation between milk yield and the average daily temperature-humidity index (THI) of the previous week. Circles represent individual observations, and dash line represents simple linear regression. All cows were housed in the same barn equipped with evaporative cooling, and fed similar lactating cow rations (Adapted from Tao et al., 2020 ).

(The Author)

Figure 4. (A) Summary of difference (kg/d) in milk yield in late-gestation heat-stressed cows relative to cooled counterparts (average difference = 3.6 kg/d; 10.3%) and (B) difference (kg/d) in prepartum and postpartum dry matter intakes in late-gestation heat-stressed cows relative to cooled counterparts (prepartum average difference = 1.4 kg/d; 12.7%; postpartum difference = 0.1 kg/d, 0.5%). Adapted from Ouellet et al., 2020 .

(The Author)

Figure 5. (A) Odds ratio and 95% CI calculated for dairy cow mortality during heat wave (HW) and in the 3 not heat wave days (nHW) after the end of heat wave (d 1, 2, and 3 defined as nHWst, nHWnd, and nHWrd, respectively). (B) Odds ratio and 95% CI calculated for dairy cow mortality in relation to the duration of exposure to heat. The duration of exposure was classified as short (1 to 3 heat wave days), medium (4 to 6 heat wave days), long (7 to 10 heat wave days), and very long (>11 heat wave days). Odds ratios are statistically significant when 95% CI does not include the unit (dashed line). Adapted from Vitali et al., 2015 .

(The Author)

Figure 6. Summary of the performance impairments associated with late-gestation heat stress for the dam (1), daughters (F1), granddaughters (F2), and dairy sector (2) reported in a series of study (where ECM = energy corrected milk). Extracted from Ouellet et al., 2020

Monitor Heifer Nutrition When Transitioning from Dry Lot to Pasture

Tue, 15 Apr 2025 17:19:01 GMT

Heifer development guidelines recommend development to promote the early onset of puberty and to develop heifers to a target body weight at the time of breeding. However, research indicates that nutritional status during the first 21 days of the breeding season may be as important as prebreeding. Heifers who gain weight during the first 21 days of the breeding season have been shown to have increased conception compared to heifers who lose weight during this timeframe.

Research from South Dakota State University found negative implications on embryonic development and survival when heifers are transitioned to a reduced gain diet directly after AI breeding. This should be considered when transitioning heifers from a dry lot to pasture, as this transition can cause changes in body weight and composition just before or at the initiation of the breeding season.

In a recent heifer development study conducted at Iowa State University’s McNay Memorial Research and Demonstration Farm, the pregnancy rates of heifers in two dietary groups were compared: a restricted group, developed to 55% of their mature body weight at breeding, and a non-restricted group, developed to 65% of their mature body weight at breeding. Due to 2023 drought conditions, heifers in the restricted group were developed on a lower energy diet in a larger pen area until adequate pasture growth for turn out 3 weeks before AI breeding. Heifers in the non-restricted group were developed in standard dry lot conditions until breeding. After AI breeding, all heifers were managed as one group on pasture.

Body weight and condition changes were collected using carcass ultrasound measurements before breeding and at the final pregnancy ultrasound diagnosis, thirty days following a 45-day breeding season.

Figure 1 shows the change in body weight and carcass ultrasound measurements for ribeye area (REA), backfat (BFAT), rump fat (RUMP), and intramuscular fat (IMF) taken in May before AI breeding and in September at the final pregnancy determination. On average, the non-restricted group lost weight while managed on pasture compared to the restricted group who continued to gain weight.

Both groups, on average, lost condition for REA, BFAT and RUMP measurements, with this decrease being larger in the non-restricted group. Interestingly, both groups continued to gain IMF while on pasture. Pregnancy results from this study found that final heifer pregnancy rates (AI bred and natural service bred) did not differ between the two groups. Numerically, more in the non-restricted group were bred by AI compared to the restricted group, but this difference was not statistically significant.

These results highlight the importance of developing heifers based on the specific management practices and goals of a cow-calf operation. Developing heifers to higher body weights resulted in more AI bred, but these heifers lost more body condition when transitioned to pasture management.

The total number of bred heifers did not differ between the groups. Developing heifers to lower body weights resulted in less extreme body condition loss when transitioned to pasture, continued weight gain, and saved $76 per head in feed costs. Final pregnancy rates did not differ between the two dietary groups. When determining the optimal body weight to breed heifers, nutritional availability and operational goals should be considered to maximize reproductive rates and operational profitability.

Your Next Read: Developing Heifers: Expectations for the Next Generation

Replacement Heifer Prices Hang in Record Territory

Tue, 08 Apr 2025 13:27:39 GMT

It’s history in the making in U.S. dairy animal trade right now, as springer values stay knocking on the door of $4,000 per head, and calf prices continue to soar. Newborn beef-cross calves are bringing north of $1,000 per head nationwide. Ironically, those calves also are at least partially the source of climbing heifer values. In the January 2025 USDA Cattle Report , lactating dairy cows showed an annual tally of about 9.5 million head, up about 3,000 head from the previous year. But the count of dairy heifers 500 pounds and over fell nearly 40,000 head as dairy producers continue to reach for beef semen to raise high-in-demand crossbred calves. That demand is fueled by a dwindling U.S. beef cow herd, which the same report noted was the smallest in 64 years.

Heifer Prices

(Maureen Hanson)

Staph. aureus is being Confirmed More Frequently as the Culprit Contributing to Subclinical Mastitis

Mon, 07 Apr 2025 20:39:06 GMT

If you look hard enough, you can find Staphylococcus aureus (Staph aureus) in at least one cow on every dairy, according to Dr. Justine Britten a PhD animal scientist working at Udder Health Systems Inc .

Despite that bold statement, Britten is not implying every dairy has a mastitis problem or is gearing up for an outbreak. Rather, she is pointing out how common the pathogen is on the farm and that it often flies under the radar, contributing most frequently to subclinical disease.

“One thing I’m still surprised about, is I think that most producers, veterinarians, and consultants know that, and they don’t necessarily,” she tells Dr. Fred Gingrich, Executive Director for the American Association of Bovine Practitioners, during a recent “Have You Herd” podcast: Managing Staph aureus Mastitis in Dairy Cows

Britten says that the prevalence of Staph aureus is increasing, based on the 7,800 bulk milk samples her company tests, on average, each year. From 2017 to 2021, the prevalence stayed relatively flat at about 20%. Today, the prevalence is more than double that.

“We’re seeing it now at around 44% to 45% of all bulk tank samples we do are positive for Staph aureus,” she says.

Consider The Heifer Population

Something Britten says has surprised her is that heifers may calve into a subclinical infection, resulting from Staph aureus, even in a closed herd.

“Being a closed herd will help reduce the chances that’s going to happen, but it’s still possible,” she says.

In evaluating literature, Britten says between 2% and 15% of heifers are going to calve in with it, and they may have a clinical episode. However, cell counts in the infected heifers tend to be low which lessens detection.

“That’s one of the most frustrating things, is that positive heifers may stay around 100,000 or less with their cell count for quite a while before it begins to climb, and that makes it really difficult for producers to get their minds around the fact that this animal is permanently infected with a contagious pathogen. It also makes the disease that much more difficult to manage,” she says.

If the dairy is not proactively screening, heifers typically recover from an episode and look fine. At that point, they are usually returned to the herd where they may infect other heifers and cows.

“My takeaway is if Staph aureus was easier to see, more like a mycoplasma, I suspect producers would be a lot less tolerant of it than they currently are,” she says.

Screen All Cows And Heifers

Britten considers a monthly bulk tank culture as the bare minimum that a dairy can do towards monitoring pathogens in the bulk tank, and she calls it an incredibly helpful tool.

“You’re really operating in a vacuum otherwise,” she says. “Even by monitoring at the bulk tank level, we’re monitoring at the 10,000-foot view. But if [the dairy] is not doing any other culturing, it’s still better than nothing.”

Britten says she is a strong advocate for screening all cows and heifers as that’s the most proactive approach to prevention.

“It works, I know that it works, but it is very important to have some kind of audit system in place, so that you get them all, not 50% of them, not 70% of them, all of them, and that you have a management plan in place for what to do with them,” she says.

On the dairies she works with that have a very low staff positivity rate, they often sell the cows.

“They’re not going to tolerate them, while for others it’s too expensive to do that,” she says. “They’re going to go into a staff pen, or with the heifers, they try and treat them and see if we can get them cleared up. But yeah, screening, culturing of all fresh cows and heifers is the best way to find those animals early and to manage them.”

Take-Home Messages

In the podcast, Gingrich and Britten discuss that in outbreak situations it is important to evaluate why cows are getting infected and remember that cows typically get infected in the parlor and focus efforts there. This includes evaluating teat condition, parlor procedures and equipment function.

Aggressive culturing programs, segregation and culling are important to minimize risk.

Britten provides these three additional take-home points, per the AABP discussion:

Take-home point #1 – Not all Staph aureus colonies exhibit beta-hemolysis, therefore, it is important that all Staph colonies undergo coagulase testing to identify Staph aureus.

Take-home point #2 – Monthly bulk tank cultures are a bare minimum monitoring program for dairy farms.

Take-home point #3 – Somatic cell count is a lagging indicator and cultures will detect infections earlier. Britten emphasized that the difference lies in management practices. Proactive monitoring, culturing, and implementing strict control measures can prevent Staph aureus from becoming a major issue, even though the pathogen is present.

For more information and recommendations, be sure to check out the podcast: Managing Staph aureus Mastitis in Dairy Cows

Calving Tips: Dealing with Protective Moms

Tue, 08 Apr 2025 13:24:28 GMT

As spring calving season continues, producers continue to monitor and assist when needed as their next calf crop hits the ground. Dealing with protective moms can be a challenging situation, two industry leaders and a producer share their tips on how to prevent and cope with the situation when faced with an unruly cow.

The first 24 hours is a key time in the newborn’s life. Ron Lemenager, Purdue beef specialist, says calves older than 24 hours are typically hard to catch, so if you plan to process the newborn, it should be done as soon as possible after birth.

“Outside of colostrum, I don’t often talk about some of the other chores that might need done in that time period,” says AJ Tarpoff, Kansas State University Extension veterinarian. “Simply because it’s different for every operation.”

Work as a team: It’s hard to know if you are in danger without someone watching your back. One person can entertain the cow, while the other can tag or accomplish what is needed.”

(Angie Stump Denton)

Depending on your management program, producers may choose to perform some of these tasks in the first 24 hours: tagging, castrating, dehorning, taking birth weights, giving selenium injections or recording calf information in a calving book.

It might be necessary to use nutritional supplements/injectables depending on the operation and cow status. Tarpoff encourages producers to discuss proper products and protocols to use at calving with your veterinarian prior to the first calf hitting the ground.

Commercial cattle producer Tyler Tobald, JTAC Farms, Glasco, Kan., shares his process for newborn calves.

“In the first 24 hours after calving, I will usually put ear tags into the calf,” he says. “If the calf is a bull, I band it. Then, I give the calf some oral vitamin A, D, E, B12 gel while I use a leg band to get its weight. We rotate our calving areas in different parts of the pasture and attached field. After I’m all done tagging, I enter the calf into CattleMax and record any other notes about the cow and calf that I deem important to know for the future.”

Obviously, cow behavior can be a factor when processing a newborn. Just like the video published with this story, sometimes a protective mom decides she is not happy with a producer touching her calf. Tobald says his goal is to keep a cow’s stress levels down as much as possible.

“I check the pair out on a side-by-side,” he explains. “When I roll up, I try to be as quiet as possible and not just zoom up on them. After that, I try to be as quiet as I can. I don’t hoop, holler, talk or anything that will add stimulation to an already stressful situation. I also always keep the cow in front of me as best as possible. The last thing I want is for an amped up 1,300-lb. animal behind me where it can sneak attack me.”

Tobald says his philosophy on dealing with cows, even the over-protective ones, is using the most important of the Roadhouse Rules: Be nice until it’s time to not be nice.

“Thankfully this is a very rare occurrence,” he says. “I make notes of any cow that is over-protective, so I know what I’m dealing with when I approach them in the future. But if the cow gets more aggressive the next year, then the calf doesn’t even get tags and gets loaded into a trailer with the cow and they go to the sale. Life is too short for crazy or mean cows.”

Lemenager explains that right after a cow gives birth, her hormones are raging.

“That’s part of the process that helps her bond to that calf,” he says. “She also needs to stimulate the calf, so it gets up and nurses. If any part of that natural process is interrupted, the cow can become very aggressive.”

Tarpoff shares these tips for dealing with overly protective mother cows.

Have some type of physical separation from mom. This might be a fence, panel, gate, truck, side-by-side. “The only truly safe location is to have a physical barrier between you and the cow while working with the calf”
Work as a team. “It’s hard to know if you are in danger without someone watching your back. One person can entertain the cow, while the other can tag or accomplish what is needed.”
Be efficient and thoughtful with the calf manipulation. “It only takes one painful bellow from the calf to set the cow off. Save potentially painful manipulations until last (ear tags or castration).
Be smart. “Don’t assume cows are faking a threat. When in doubt, always take the safe approach. The chore can always be completed later if the cow is on the fight. Keep records and plan to handle the situation when she calms down.”
Stay safe. “If we get injured, we put stress on the rest of our family and operation.”

Different strategies can help keep the producer and calf safe during newborn processing.

“Some ranchers use a cage on the side of their ATV,” Lemenager explains. “This allows for bringing that calf into the cage while handling it. Another option is to have two people working with the calf. One to care for the calf and the second to keep the cow away.”

If you are going to try to move a calf to another location, an option is a polypropylene plastic sled or a calf carrier on an ATV (calf sling). Lemenager says a cow will typically follow because she can smell and see her calf.

“Ideally, when working with a cow-calf pair, I try to keep the calf between me and the cow,” Lemenager says. “Most, but not all cows, are calmer and less aggressive when they can see and smell their calf.”

Lemenager summarizes a key to improving your cow herd behavior is to consistently use low-stress handling to help desensitize cattle to the presence of people.

Follow Tobald or JTAC Farms on Facebook or TikTok for more examples of low-stress handling and cow management.

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Managing Heifer Inventories to Maintain Herd Size

Thu, 03 Apr 2025 19:15:45 GMT

Market costs for replacements are at an all-time high, ranging between $3,000 and $4,000 per head. Iowa State University Extension calculated heifer raising costs in 2024 to be just over $2,600 for 24 months. The difference in the expenses provides a financial opportunity for dairy farms that can raise their own replacements. Heifer inventories need to ensure that herd size is maintained. The amount of heifers needed on the dairy to maintain herd size is highly impacted by age at first calving and herd culling rates.

Age at First Calving

Heifers are unique to the farm in that they are the future of the dairy farm but do not provide income to the farm until they have their first calf. The optimal first calving age ranges between 22 and 24 months. According to Iowa State estimates, reducing the age at first calving by a month will save the dairy $93 per heifer. However, research has shown that calving too early (< 21 months) would hurt profitability in the long run because heifers would not reach their full milk production potential.

Proper growth rates are extremely important to reach optimal age at first calving. Body weight determines when heifers reach puberty, around 45 to 50% of mature weight. Too low of average daily gain can delay puberty, which then will have a snowball effect by delaying time to first breeding and age at first calving.

Delaying the age at first calving costs money and increases the heifer inventory needed to maintain herd size. A herd of 100 milking cows needs 5 to 6 more additional heifers for every two-month increase of age at first calving when their culling rate is 30%.

Culling Rate

To no surprise, the rate at which animals leave the herd has a significant impact on the replacement inventory. A herd of 100 milking cows with an age of first calving of 24 months needs an additional 4 to 5 heifers with every 2% increase in culling rate. Therefore, increasing the culling rate from 22% to 32% would require 22 additional heifers to keep the milking herd size at 100.

High market prices for heifers can significantly increase farm income for farms with excessive replacements. However, heifer inventories should be monitored closely. Small changes in culling rate and age at first calving significantly impact the number of replacements needed.

Your Next Read: The 5 Big Market Trends Dairy Farmers Need to Keep Their Eye on this Year

Where Will the Replacement Heifers Come From?

Tue, 25 Feb 2025 15:05:33 GMT

An unprecedented shift in the U.S. dairy cattle population could signal uncertainty ahead in terms of milk production, cow numbers, and prices – for both the milk and the animals.

At the center of the current conversation: heifers, and more specifically, lack of them. In the most recent USDA Cattle Inventory report, released January 31, 2025, the inventory of dairy heifers weighing 500 pounds or more totaled just 3.914 million head. That’s the lowest count for that population since 1978.

Included in the total are heifers expected to calve into the milking herd in 2025, estimated at 2.5 million head. That figure has dropped precipitously every year since 2017, when about 600,000 head of additional heifers freshened. The current number of heifers expected to calve is also the lowest since the USDA began tracking that figure in 2001.

The shift in heifer population nearly identically mirrors the adoption of beef crossbreeding to add more value to non-replacement dairy cattle. It’s currently doing just that. With the U.S. beef cow herd size also hovering at near-historic, low levels, demand for those beef-cross calves is high, leading to almost-unheard-of prices of $1,000/head or more for newborn calves.

Likewise, springing heifers are scarce -- and expensive -- on the open market. Holstein springers started topping $4,000/head on the high end in Pipestone, Minn. toward the end of 2024. And at the Turlock Livestock Auction Yard’s January Dairy Video Sale in Turlock, Calif., potloads of Holstein and Jersey springers brought an average of $3,650-3,700 and $2,750-2,900/head, respectively.

Tight heifer supplies mean herds are generally creating just enough heifers to meet their projected replacement needs. Meanwhile, the nation’s milking herd is not growing, continuing to hover at around 9.35 million head.
What remains to be seen is whether an aging dairy herd will affect total milk production if producers hang onto cows longer before marketing them for beef. Any hiccup, like bird flu or another unforeseen challenge, could leave producers scrambling to maintain herd size.

Finally, while many factors remain in play, one benefit of the changing supply-and-demand dynamic could be a boost in milk prices. The all-milk price forecast for 2025 is $23.05 per hundredweight, up about 50 cents year-over-year. A shift in heifer supplies will take at least two years to happen, so those benefits could be enjoyed relatively long term.

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The Importance of Tracking Heifer Growth

Wed, 22 Jan 2025 20:45:19 GMT

Growing dairy replacement heifers is no longer the “one-size-fits-all” proposition that it was once assumed to be.

Today, we know that simply using breed-average standards is less than ideal for individual herds and their unique animals. To help dairies evaluate their heifers and raise and breed them to best serve their specific needs, Penn State University has developed a free, customizable, online spreadsheet to track heifer growth.

“If you can use Excel, you can use it,” stated Gail Carpenter, Assistant Professor of Extension and Outreach at Iowa State University and host of The Dairy Podcast Show . “It’s an excellent, easy-to-access tool that can provide great value to dairies.”

Developers Jud Heinrichs and Coleen Jones noted that certain physiological changes like the start of puberty happen not because a heifer reaches a particular weight or age, but because she has matured to a certain proportion of her final, mature body size and composition.

Mature size is a lynchpin in the program. Many herds underestimate the height and weight of their mature cows; it should be assessed specifically rather than relying on breed averages. “If we know the mature size of a heifer and her current size, it is a relatively simple matter to figure out what growth rate we need to achieve to move from the current size to the mature size,” said Heinrichs.

Times in between, such as breeding, can be benchmarked as well, and the spreadsheet generates a customized growth curve for an individual herd based on that herd’s goals for age at first calving. The spreadsheet is based on the following target metrics:

Body weight of 55% of mature weight at first conception and 85% of mature weight after first calving.
Height of 55% of mature height at birth and 96% of mature height at first calving.
50% of height growth from birth to calving is assumed to occur between birth and 6 months of age, with an additional 25% between 6 and 12 months, and the final 25% between 12 months and calving.

These targets were derived from a comparison of heifer growth data from all breeds to mature heights calculated by assuming mature body weight and using research-validated ratios between withers height and body weight.

Withers and hip height are assumed to change at the same rate throughout the growth phase, so either one can be used to monitor growth, as long as the same standard is used for heifers and mature cows. Mature cow size can be entered as herd average or individually for each animal’s dam.

Heinrichs said the spreadsheet’s greatest benefit is tracking heifer progress and monitoring whether they are hitting growth targets as they develop, rather than waiting to measure heifer performance at first calving. Nutrition, housing, and sales decisions can then be made to steer heifer development and inventories.

The spreadsheet – including metric and Spanish language versions -- can be accessed here .

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Retained Placenta in Beef Cattle

Tue, 14 Jan 2025 18:53:07 GMT

Retention of fetal membranes, or retained placenta, in cows usually is defined as failure to expel fetal membranes within 24 hours after parturition. Normally the expulsion occurs within eight hours after delivery of the calf. The placenta is retained when the cotyledons on the placenta do not detach from the caruncles on the uterus during parturition. Retained placenta is rare in most cow herds.

Retained placenta creates the potential for problems. It hangs from the vulva which permits manure and micro-organisms from the manure into the uterus. Also, when the cow lays down in dirt or mud which is loaded with bacteria, it permits bacteria to cause infection in the uterus and can have serious negative consequences. Infection in the uterus can cause the cow to become ill (fever, weight loss, etc). In severe cases of infection the cow can actually die. When the uterus becomes infected and inflamed, it takes longer for the cow to clean and be ready for the next breeding season. Retained placentas can result in delayed rebreeding or cows coming up open at the end of breeding season.

Bottomline: retained placentas jeopardize reproductive efficiency and can rob operations of profit potential.

Typical causes of retained placenta

Dystocia. As a result of too large a calf, twins or abnormal presentation of the fetus, calving difficulty is a cause.

Poor nutrition. Inadequate consumption of energy or protein during pregnancy can result in thin cows. Dietary deficiency of Vitamin A, Selenium, Iodine or Vitamin E have been linked to retained placenta. Retained placenta is most often associated with nutrition, in particular, low levels of Vitamin A or the mineral Selenium.

Stress, obesity and genetics can play a role.

Infectious diseases like Brucellosis, Leptospirosis, IBR virus or BVD virus.

What are the best management practices to prevent retained placenta?
Over time, proper nutrition, herd health and mineral supplementation should solve most the problems. Typically the best source of vitamin A for cattle is green, leafy forage. A good quality free choice mineral supplement containing Selenium is advised. Cows and heifers in Body Condition Scores of 5 to 6 at calving time is advised. If you are dealing with sick cows as a result of retained placenta, consult your veterinarian for best treatment options.

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Some California Veterinarians Say Virus-Hit Dairies See More Abortions in First-Calf Heifers and Dry Cows

Mon, 06 Jan 2025 20:02:36 GMT

Triple-digit temperatures lasting for days and then weeks helped fuel a firestorm of highly pathogenic avian influenza A virus (HPAI A H5N1) cases on California dairy farms last summer.

“August wasn’t too bad, September was kind of rough, and then early October was severe,” recalls Dr. Maxwell Beal. “I think part of the problem was the cows had little relief from the heat even at night.”

But even with the onset of winter, Beal, with Mill Creek Veterinary Services, Visalia, Calif., adds that, “Cooler temperatures haven’t slowed the spread.”

Indeed, cases of the virus continue to trend upward in California. The state, the single largest producer of milk in the U.S., with 1,300 commercial herds and 1.7 million milk cows, holds the dubious distinction of being the current epicenter for HPAI H5N1.

As of Dec. 19, 2024, the California Department of Food and Agriculture had confirmed 650 dairy cowherds – roughly half of the commercial herds in the state – had been infected with the virus (see AHFSS - AHB - H5N1 Bird Flu Virus in Livestock - CDFA).

Bovine Veterinarian talked with several veterinarians in the Golden State and elsewhere about what their herds, producers and farmworkers have experienced and how they are addressing the virus. This is a summary of what practitioners shared.

Younger Dairy Animals Are Being Affected, As Well As Lactating Cows.

Among production animals on the dairy farm, lactating cows have taken the brunt of the virus infections so far, but that doesn’t mean other segments in cowherds aren’t or can’t be affected.

“I’m hearing reports from California veterinarians of sick young calves and challenges with cows resuming production and reports of dry cows aborting,” says Dr. Barb Petersen, owner and operator of Sunrise Veterinary Service, Amarillo, Texas. Petersen helped confirm the first case of HPAI H5N1 identified in U.S. dairy cattle last spring.

One of those reports came to her from Beal in California.

“I tell people, ‘Don’t sleep on your heifers, calves or your bulls, because there could be issues that we don’t know about yet simply because that’s not been our focus,’” says Beal, who reports that his virus-hit dairies have all experienced an uptick of abortions in first-calf heifers.

“One thing that happens at every affected dairy is we lose more calves, that were already called pregnant, and they’ll be all over the map as far as gestational age,” he says.

“It happens to dry cows, it happens to big calves, and these heifer abortions were all at 180- to 220-days (DCC), somewhere in there,” he adds. “Whether that’s directly caused by the bird flu or it’s caused by the clinical symptoms of the flu, I don’t know. And it’s the same for other veterinarians in our practice to the point that we will go back and reconfirm pregnant animals that we had already reconfirmed.”

Dr. Blaine Melody has had similar experiences: “We’ve consistently seen more early embryonic death and fetal loss at various days of gestation. We have recommended clients switch from long-acting dry cow tubes to lactating if we’re given the heads up before clinical outbreak, via early non-negative bulk tanks,” says Melody, a partner at Lander Veterinary Clinic, Turlock, Calif.

The Virus Amplifies Existing Health And Management Issues.

While HPAI H5N1 is associated with high morbidity and mortality in birds, this hasn’t been the case for dairy cattle in most regions of the country. Most affected animals reportedly recover with supportive treatment, and the mortality/culling rate has been low at 2% or less, according to the American Veterinary Medical Association.

That percentage fits with Beal’s experience in California, but dairy producers in some parts of the state have reported higher mortality levels. Some have experienced cow mortality rates as high as 15% or 20%, according to a Reuters article published in October. See Cows dead from bird flu rot in California

“Cows that get H5N1 are compromised, so any other health issues that are present in the dairy increase,” Beal explains. “Staph aureus, mastitis, mycoplasma, all of them go up.”

“The virus takes the problems that are already on your dairy that you’ve either figured out how to cope with or they’re just sitting at a low level, and it exacerbates them for probably a month,” he adds.

Melody says management quality plays a huge role in what producers and their employees must deal with when the virus hits.

“If you have overcrowded pens, bad cow comfort, poor nutrition management, poor transition cow management or any other underlying risk factors, you will have a worse outcome with a clinical HPAI outbreak. That’s a given,” he says.

In mid-December, California Gov. Gavin Newsom declared a State of Emergency to address the virus in California dairy cattle, ramping up monitoring, quarantine efforts, and resource deployment. See California Issues State of Emergency Warning in Response to More Bird Flu Found on Dairies

The number of farmworkers infected with the virus is likely higher than what’s being reported.

Officially, there have been 66 confirmations of human being infected by the virus in the U.S. See H5 Bird Flu: Current Situation

Melody, Beal and other veterinarians told Bovine Veterinarian they have seen presumed infected employees on farms working with cows.

“Some of these workers are at potential risk, because we don’t know all the ways this virus is spreading yet,” Melody says.

“They just put their heads down and work, so they can keep their paycheck,” Beal adds.

Drenching Cows Can Help, But Rest Can Do As Much Good In Some Scenarios.

Both Beal and Melody say drenching can help clinical HPAI cows, but veterinarians and their producers need a good plan for the treatment to work well.

Beal says there is a significant learning curve for people who have never or seldom drenched a cow. Employees on some of the infected dairies he works with went from never using the practice to suddenly treating hundreds and even thousands of cows a day.

In that intense scenario, Beal says it’s nearly impossible for employees to succeed.

“When you run a drench hose through 1,000 cows, you will not do as good a job with that last cow as you did with the first one,” he explains.

There is real potential to cause more harm than good to the animal physically, Melody adds.

“Drenching can help, but if you’re locking cows up too long or drowning cows because you’re drenching lots of cows and you’re exhausted, that undoes any good you’re trying to accomplish,” he says.

Beal says after working with a couple of outbreaks, he decided to try a different approach.

“We started to use a let-the-cows-rest approach, and I felt like we were still doing just as much good for the animals and not exhausting our staff in the process,” he says.

However, he continued to encourage workers to drench the ones that were clinically dehydrated or exhibiting signs of duress.

“I would say the ones that showed clinical signs to the degree that they warranted treatment has averaged around 30% in a herd,” Beal says. “The ones that are obviously clinically affected we need to treat, but not necessarily the ‘she’s got a runny nose,’ cows.”

What Is Your Definition Of Disease?

Melody says one of the challenges is how veterinarians and producers define disease as well as their definition of severity. With regard to HPAI H5N1, he has observed inconsistent practices and varied approaches to reporting, because people don’t have a consistent benchmark for reference.

“When you get HPAI on dairies, every cow that gets sick is then called a flu cow, but you can’t conflate that it’s all influenza,” he says.

Melody also encourages practitioners to keep a tight rein on their treatment protocols and to maintain consistent practices with regard to regulations.

“If you make things gray, when it comes to regulatory standards, we can quickly start to spiral, because you start going, ‘Well, we made this exception for this, so why not here too?’” Melody says. “Stay with your established playbook, and don’t deviate from it.”

Melody and Beal both say they have been frustrated at times by slow turnarounds by state laboratories responsible for providing test results. Their advice: Be a squeaky wheel with regard to getting virus test results.

“Many testing labs are overrun with samples, and the process gets bogged down, or the results don’t get to the veterinarian because of confidentiality rules,” Melody says.

“Some people are shipping animals that are infected but don’t know it because they didn’t get the information back in a timely fashion from the bulk tank tests,” Beal adds. “There needs to be a reworking of the testing protocols.”

Nutrition And Cow Comfort Practices Can Help Affected Animals Return To Good Production Levels.

Melody and Beal say most of their clients’ cows return to a good level of production post infection.

“Now, do they all come back 100%? No, I haven’t seen that on any of my dairies,” Beal says. “If people compare production now to last December, there’s likely a deficit. Some of the cows are ending up 5 lb. to 6 lb. under where they were this same time last year. That’s not unusual.”

Beal adds that veterinarians who can talk with their clients about what ramifications to expect from the disease, before it ever reaches their herd, can probably save a significant number of cows from being culled in the future.

What can improve that scenario for virus-impacted cows in the future is investing dollars in nutrition and facilities as farm resources permit, Melody adds.

“Renovate your dry cow barn, put some shade over those animals, put a little extra metabolizable protein into the fresh cows right now to make sure they’re getting off to a good start,” Melody advises. “Do good management, the things that you know are going to make your cows strong. Those things will pay for themselves whether you’re in the midst of a virus outbreak or wanting to help cows in the long-term.”

____________________________________________________________________________

‘No Established Gold Standard’

Dr. Blaine Melody, a partner at Lander Veterinary Clinic in Turlock, Calif., says somatic cell counts (SCC) are not a gold standard for defining parameters of the HPAI A H5N1 virus. He says SCCs can be wildly different for each farm because of management differences — whether dumping not dumping milk, sturdy versus frail cows, good or bad preexisting milk quality practices.

“My goal is trying to get as close to an apples-to-apples comparison between farms, and you can only decipher that by knowing the farms and asking more questions when people start throwing numbers around,” he says.

Melody offers one real-life example from his experience:

“Two dairies get HPAI at the same time,” Melody says. “One farm gets hammered with a 15% cow clinical mastitis case rate for the duration of the epidemic. The other farm may say it never had any HPAI clinical mastitis cows and only treated a handful of febrile cows with no milk, respiratory or GI disease. You look at their records and can confirm that to be ‘true.’ You ask more questions and also learn that the primary method of identifying mastitis is different between those two farms: the first farm strips and visually screens each quarter for abnormal milk, while the second does not and relies solely on milk conductivity sensors.”

“The vast majority of these clinical cows in our area are mild cases of mastitis with no effect on the udder or cow,” he adds. “This thick, clinical HPAI milk did not get flagged with conductivity sensors. Even within the same brand there can be modified settings farm to farm. The truth in this example ‘lied’ in the salable milk quality when their SCC more than doubled.

“The importance is understanding the farm management differences and knowing what further questions to ask rather than jumping at naked numbers that are often without clear denominators,” Melody says.
____________________________________________________________________________

200-Plus Mammal Species Infected

While researchers have learned a lot about HPAI A H5N1 since its confirmation in a Texas dairy herd in March 2024, much is still unknown, including the various ways the disease might spread and which animals it infects.

According to USDA’s APHIS, in addition to dairy cows, more than 200 other mammal species in the U.S. have been infected by the virus since 2022. One of the hardest hit animal populations on farms are barn cats, which often consume colostrum and raw milk, not to mention potentially infected birds and vermin.

Other U.S. mammals infected with the virus include a bottlenose dolphin, foxes, bobcats, mountain lions, coyotes, skunks, harbor and grey seals, opossums, squirrels, minks, otters, black bears, brown bears, polar bears, and a single pig on a backyard farm in Oregon, confirmed in late October.

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Tips To Help Ensure Heifers Breed Back After Calving

Thu, 02 Jan 2025 19:59:25 GMT

When it comes to first-calf heifers, nutrition matters big time.

“These new moms have incredibly high nutrient requirements,” says Kirk Ramsey, veterinarian with Neogen . “Not only are they still growing, but lactation takes it to a whole new level.”

Ramsey suggests separating and supplementing them away from the mature cows in order to meet those demands.

In addition, body condition score is key.

“Heifers with a body condition score of six at calving are way more likely to breed back on time,” Ramsey says. “Let’s make sure to be tracking that.”

Early breeding season is also a win-win, according to Ramsey.

“Start the season earlier for heifers,” he says. “Heifers bred within 21 days of the first breeding cycle are more likely to breed back. They’re going to wean heavier calves, and it’s even shown that they’re going to last longer in our herd.”

Lastly, producers should address energy demands as early as possible.

“Energy requirements at calving skyrocket almost immediately, and compensating for poor condition after calving is nearly impossible,” he says. “Focus on the last months prior to calving to make any condition adjustments that you need to. By nailing these couple points, we boost their breeding success, leading to a healthier herd, heavier calves, and a more profitable operation.”

Your next read: Calving Signs in Cows and Heifers