Beef Heat Stress

Keep Animals Safe and Healthy During Excessive Heat

Thu, 24 Jul 2025 20:11:47 GMT

Excessive heat will once again blast much of the U.S. this week, with heat indices predicted to reach 110 degrees Fahrenheit or more in many locations. University of Illinois Urbana-Champaign animal welfare expert Angela Green-Miller says pets and livestock are at risk, and it’s up to humans to keep them safe.

Green-Miller runs the Animal Welfare, Environment, and Sustainability Laboratory as an associate professor in the Department of Agricultural and Biological Engineering, part of the College of Agricultural, Consumer and Environmental Sciences and The Grainger College of Engineering at Illinois.

Green-Miller answers common questions from pet owners and livestock producers.

First of all, how do animals cool themselves?
Different animals use different methods, but some broad brush-strokes for all animals include seeking shade and shelter, lowering activity and feed intake to keep metabolism down, and drinking more water. Any of the cooling strategies we would use, they would use too.

Don’t some animals not sweat? How do they keep cool?
That’s true. Dogs and pigs, for example. They dissipate heat through panting, defecation, and urination. They may increase those activities, which makes it that much more important to replenish their water supply.

What can humans do to help animals when it’s hot? Let’s start with pets.
Anything you would do for yourself, you could do for them. Bring them into the air conditioning, if possible, make sure they have access to plenty of water, and try to have them rest indoors or in the shade during the hottest part of the day. For outdoor animals, shade is critically important. Also, if they can be elevated from hot surfaces, such as on an elevated bed, that will let air circulate around them and remove some of that heat.

What about livestock?
We need to make sure the air is moving, bringing fresh air into the barn, even if it’s hot outside. The animals are contributing energy and heat into the environment, so the more of that we can move out, the better. And moving air over their body surface helps them release some of that energy.

For animals in indoor confinement, producers can alter lighting and feeding schedules. The idea is for them to rest during the hottest part of the day, so keep the lights down and withhold feed until it starts to cool down. That’s not an uncommon strategy, but there may be some producers out there who could use a reminder.

It’s also critical to ensure that water lines are working and that there’s fresh water flowing. Double-check those drinkers a little more frequently to make sure they’re not clogged. This is the time of year when we emphasize the critical nature of maintenance. If there’s any deferred maintenance, bump it up to the top of the priority list because a broken fan in this type of weather is one of the worst situations we can have.

What are the potential economic impacts of excessive heat on the livestock industry? Are there predictable dips in productivity every summer?
Absolutely. Feed intake is reduced during heat events, so we see dips in productivity. They’re also losing energy in the form of heat instead of putting it toward growth. We see reproductive impacts as well. Breeding rates tend to drop whenever there’s a heat event, and sometimes we see gestational impacts as well, especially in animals that are late in gestation.

Early Shedding Cows Produce Heavier Calves at Weaning

Thu, 22 May 2025 14:08:04 GMT

Early summer hair shedding is a proven trait of economic relevance for producers in areas of increased heat and humidity and those grazing endophyte-infected (hot) fescue. University of Missouri research indicates hair shedding is important to more than just Southern cattle producers.

“Animals who shed their winter hair coat sooner are less likely to be exposed to heat stress in the summer,” says Jamie Courter, University of Missouri beef genetics extensions specialist. “These animals are also more likely to wean heavier calves and remain productive in a herd, for longer.”

Figure 1 shows the average weaning weight of calves born to dams who began shedding their winter coats between March and July. The average weight of a calf born to a dam that shed in March was 57.2 lb. heavier than those that shed in July.

Figure 1 shows the average weaning weight of calves born to dams who began shedding their winter coats between March and July.

(University of Missouri)

Research at the University of Missouri has found a relationship between hair shedding scores and length of daylight. Thus, hair shedding may serve as an indication of an animal’s ability to sense and respond to their environment.

Courter says the relationship makes hair shedding useful for producers outside the Southern U.S.

Hair-shedding Scores

Hair-shedding scores represent a visual appraisal of the extent an animal has shed their winter coat. Reported on a scale of 1 to 5, the lower the assigned score, the more hair an animal has shed. Half scores, such as 3.5, are not reported.

Hair shedding scoring system.

(. Adapted from Durbin et al., 2020. Genetics Selection Evolution 52:63)

Cattle tend to shed hair from the front to the back and from their topline to their belly (Figure 3), but there is individual animal variation in this pattern. Typically, animals begin shedding around their neck, followed by their topline. The last spots to shed are an animal’s lower quarter above its hock and its underline.

Figure 3. Diagram of typical hair shedding regions in cattle aligned to their hair shedding score. Cattle shed from head to tail, top to bottom, with some variation. Numbers represent areas where hair would be expected to shed for a given score.

(University of Missouri)

Courter says the time to evaluate cattle for hair shedding will vary by geographical location and environmental conditions. Animals should be scored when the most variation exists within the herd.

“There should be a few animals who receive a score of 1, a few who score a 5 and a majority receiving a hair shedding score of 3,” she explains.

Cattle begin shedding their winter coat in late spring through the summer. For many locations, mid-May has been identified as an ideal hair-shedding evaluation period. The hotter and more humid the climate, the earlier in the spring scores should be collected.

Hair shedding is a moderately heritable trait (h2=0.35 to 0.42). This means that incorporating a hair-shedding score into culling and replacement heifer selection decisions will result in genetic change over time.

“Although hair shedding has traditionally been associated with heat stress and fescue toxicosis, recent research shows this quick and easy phenotypic assessment of cattle could be a trait of even more economic importance,” Courter says. “With its moderate heritability, combining this score with a hair shedding EPD or score on bulls would result in positive genetic progress over time.”

Your Next Read: Spring Pastures Alert: Be Aware of Frothy Bloat Risk

Hair Shedding Can Affect Cattle's Heat Tolerance As Well As Profitability

Thu, 12 Sep 2024 15:42:14 GMT

Responsible beef breeding requires matching cattle genetics to the production environment. This is necessary for at least three reasons: profitability, animal well-being, and improved environmental impact. Cattle that are well-suited to their environment are more profitable. Not only are well-adapted cattle more productive, but they also require fewer inputs and interventions. It is estimated that cattle suffering from fescue toxicosis, and heat stress alone cost the beef industry over a billion dollars a year, according to research by MU Extension.

One way to manage animals for heat tolerance is looking at hair shedding.

Early summer hair shedding is a proven trait of economic relevance for producers in areas of increased heat and humidity and those grazing endophyte-infected (hot) fescue. Animals who shed their winter hair coat sooner are less likely to be exposed to heat stress in the summer. These animals are also more likely to wean heavier calves and remain productive in a herd, for longer. More information on hair shedding and heat tolerance can be found in MU Extension publication G2014, Hair Shedding Scores: A Tool to Select Heat Tolerant Cattle guide sheet.

More recently, a relationship between hair shedding scores and length of daylight has been found. Hair shedding may serve as an indication of an animal’s ability to sense and respond to their environment. Such a relationship would make hair shedding useful for producers outside the southern U.S.

Cattle shed from head to tail, top to bottom, with some variation. Numbers represent areas where hair would be expected to shed for a given score.

(MU Extension)

When is the best time to score my animals?

The time to evaluate cattle for hair shedding will vary by geographical location and environmental conditions. Animals should be scored when the most variation exists within the herd. There should be a few animals who receive a score of 1, a few who score a 5, and a majority receiving a hair shedding score of 3. Cattle begin shedding their winter coat in late spring through the summer. For many locations, mid-May has been identified as an ideal hair shedding evaluation period. The hotter and more humid the climate the earlier in the spring scores should be collected.

How often do I score my animals?

It is recommended that hair shedding scores be obtained on the whole herd once a year. While additional data is never detrimental, based on estimates of the heritability (h2 = 0.35 to 0.42) and repeatability (r = 0.44) of hair shedding, at least three years of data collection on an animal is ideal for genetic evaluation purposes.

How does age affect hair shedding?

Yearlings and first calf heifers tend to have higher hair shedding scores compared to older, established cows. This does not necessarily mean that younger animals should be culled right away. Younger cows are, by default, the most nutritionally stressed as they are growing/raising a calf while also growing themselves. Keeping that in mind, hair shedding scores can be used to rank and select females within an age group, but likely shouldn’t be used across the whole herd.

Should I score my bulls?

Providing half of the genetic potential to the next generation, obtaining a hair shedding score on bulls is of equal importance. For seedstock breeders, this serves as an act of customer service for potential buyers as well as knowledge for your breeding program. For commercial producers, it is an opportunity to make informed purchasing and breeding decisions. Please note that males tend to start shedding approximately two weeks before females.

What if I do not graze endophyte-infected fescue?

The genetic correlation of hair shedding while cattle are or are not grazing hot fescue is 0.93. Furthermore, when treated as two different traits, the estimated breeding value (EBV) for hair shedding either on or off fescue is 0.99. Therefore, hair shedding on or off endophyte-infected fescue can be treated as the same trait.

What if I do not live in the Southeastern U.S.?

Due to its association with heat tolerance and fescue toxicosis, hair shedding has been identified as a regional trait of interest. The genetic relationship between hair shedding score and daylight may allow these scores to indicate an animal’s ability to adapt to changes in their environment. This would make hair shedding a globally applicable selection criterion.

What if I do not have a hair shed EPD to use?

Hair shedding is a moderately heritable trait (h2 = 0.35 to 0.42). This means that incorporating a hair shedding score into culling and replacement heifer selection decisions will result in genetic change over time.

This information was compiled from University of Missouri Extension. Original authors include Jamie Courter, State Beef Genetics Extension Specialist, Jared Decker, Associate Professor, Animal Sciences and Jordan Thomas, Assistant Professor, Animal Sciences.

For more information on hair shedding visit MU Extension.

Working with Cattle in the Heat

Thu, 12 Sep 2024 15:42:14 GMT

As temperatures rise across the country and many regions are seeing triple digits, plus high humidity, cattleman producers are thinking of ways to keep themselves and their livestock comfortable.

Paul Beck of Oklahoma State University Extension offers information about how to evaluate cattle comfort and best practices for working cattle in the heat.

Beef Cattle Temperature Humidity Chart

(Eirich and Woosoncroft, University of Nebraska Cooperative Extension)

The Beef Cattle Temperature Humidity Chart (Figure 1), which helps determine the risk level of heat stress given the temperature and the relative humidity. The higher the humidity the lower the temperature that is cause for concern.

In hot summer conditions, heat transfer failures cause accumulation of body heat resulting in heat stress, reduced performance, animal discomfort, or death. When animals experience discomfort from heat stress, their behaviors change to reduce heat load (increased water consumption, decreased feed intake, seeking shade, standing in water, etc.), Beck says.

The USDA Meat Animal Research Center published a scoring system to define heat stress in cattle based on panting score. This is a good indicator of heat stress because panting increases as the heat load increases. This scoring system is from 1 to 6, with 1 being slightly stressed to 6 being near death.

Score—Description
0—Normal respiration, no sign of heat stress
1—elevated breathing rate, restless, spend increased time standing
2—elevated breathing rate, slight drooling, most animals standing in pen and restless, animals may group together
3—elevated breathing rate, excessive drooling or foaming, most animals standing in pen and restless, animals may group together
4—elevated breathing rate, open mouth breathing, possible drooling, most animals standing in pen and restless, animals may group together
5—elevated breathing rate with pushing from flanks, open mouth breathing with tongue protruding, possible drooling, most animals standing in pen and restless
6—open mouth breathing with tongue protruding, breathing is labored, respiration rate may decrease with pushing from flanks while breathing, head down, not necessarily drooling, individual animals may be isolated from herd

Water
Water intake per unit of feed intake is twice as high during the summer than in the winter. Evaporation of moisture from the respiratory tract through panting is an important way for the animal to lose excess heat load. So, during heat stress water space availability becomes very important. During heat stress the linear water space increases from about 1 inch per head to 3 inches per head to allow for sufficient access to water. When temperatures are above 40° F, water intake should increase by 1 gallon for every 10° F increase in temperature.

Shade
Shade has been found to be beneficial to feedlot cattle, the greatest benefit of shade for finishing cattle is at the onset of the heat stress event. Cattle with shade have lower respiration rates and body temperatures when temperatures increase. Under heat stress, shaded finishing cattle in feedlots have increased average daily gain, hot carcass weights and dressing percentage as well as improved feed efficiency.

Space
Cattle require 1.8 to 9.6 square yards per head depending on the size of the animal. Effective shade structure design depends on the thermal properties of the shade material, the ground cover under the shade, height of the structure, the amount of shade provided per animal, the level of ventilation (lower ventilation can trap heat under the structure), and the orientation of the structure. Shade structures should be at least 12 feet high to reduce direct solar radiation and increase air movement in the shelter. Metal shades effectively block direct solar radiation, but it can accumulate heat and radiate it on the animal. Shade cloth allows more air movement and heat dissipation. Providing shade, if designed correctly, is an effective strategy to reduce heat load by reducing heat accumulation from direct solar radiation and has animal welfare benefits that can improve performance.

Time
Finally, cattle handling should occur in the early morning before temperatures get too high. If there is little to no night cooling, cattle handling operations should be delayed until better conditions exist. Work cattle in small groups so that no groups are in holding areas longer than 20 to 30 minutes. Cattle should be handled easily to reduce stress and elevating core body temperature through increased activity.

Beck reminds livestock producers if you are not comfortable neither are your livestock, so take steps to increase comfort of livestock during heat stress events.

For more info:
https://extension.okstate.edu/fact-sheets/estimating-water-requirements-for-mature-beef-cows.html

https://beef.unl.edu/beefwatch/heat-stress-handling-cattle-through-high-heat-humidity-indexes

https://www.ars.usda.gov/plains-area/clay-center-ne/marc/documents/heat-stress/recognizing-heat-stress/

Survive the Heat Wave: Expert Tips to Protect Cattle from Heat Stress

Thu, 24 Aug 2023 14:17:36 GMT

The heat is no joke, especially for cattle producers across the country as they look for ways to keep cattle cool and comfortable.

According to the USDA Agricultural Research Service’s U.S. Meat Animal Research Center, in partnership with the National Oceanic and Atmospheric Administration (NOAA) National Weather Service, heat stress forecasts are and will continue to affect major cattle producing states over the next several days.

Heat Rages On

Producers in the middle and lower Great Plains region, as well as those in the Southeast, can expect “emergency” levels of heat through the middle of next week. A large portion of the U.S. will continue to experience alerting and dangerous levels, as well.

Based on a poll of cattle producers , many of the areas suffering dry or droughty conditions will remain at the heat stress epicenter.

One rancher, based north of Forth Worth, Texas, says his area has been scorched since late June, and feeding hay for 22 of the past 25 months is “getting old and very costly.”

Additionally, in central Texas, Pam Newman Williams notes pastures are terrible and with triple digit temperatures, there’s a severe fire danger.

Unfortunately, much of the U.S. will not see any large precipitation levels over the next seven days, according to the NWS Weather Prediction Center, with little to no relief to dry areas.

(Farm Journal)

Combat the Heat

Cattle producer, Derek Pohl, Dorchester, Neb., has turned to water to help protect livestock during these stressful heat events.

In a video posted online, Pohl shows a portable water tank with a sprinkler attached spraying water on cattle in a pen.

Pohl notes he’s hauled almost 15,000 gallons of water so far to try to keep animals comfortable. While the lots aren’t pretty, it’s keeping cattle alive, he adds.

Along with spraying water on cattle in pens, there are additional considerations when working to help cattle through the heat.

The University of Nebraska-Lincoln shares five things that may help your livestock in heat events.

1. Water—Not only is water effective when sprayed on livestock, it’s imperative that cattle have access to plenty of clean water and that there is enough access space for all cattle, including calves, to get the water they need.

2. Shade—If possible, move cattle to a pasture that offers shade, or use portable windbreak panels to help provide shade.

3. Air Movement—A slight breeze can make a world of difference, so give cattle the opportunity to get a little wind, if there is one.

4. Surface—Access to surfaces with vegetation will keep cattle cooler.

5. Additional Stress—Consider rescheduling any events that might add stress to cattle, including gathering, weaning or preconditioning.

While keeping livestock cool is a priority, be sure to take care of yourself as well. Consider these five things and apply them to your work on the operation. Stay hydrated and stay safe.

Read More:

Help Cattle Cope With Extreme Heat

Scorched to Belly-High: Cattle Producers’ Inside Look at Pasture Conditions