Identifying feedlot lameness

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Editor’s note: First in a two-part series

Lameness in feedlot cattle can seem like a never-ending battle, but sometimes that may be due to misidentification of what is causing the lameness and/or handling and treatment protocols that aren’t effective.

USDA’s National Animal Health Monitoring System Feedlot ’99 study indicated that 92 percent of all feedlots reporting had at least one animal develop lameness following arrival to the feedlot, which accounted for 1.9 percent of all cattle on those feedlots. Though the study did not break out different types of lameness, it indicated that the overall medicine cost to treat one sick animal for lameness across all sizes of feedlots was $7.68.

Two of the biggest causes of lameness in cattle are toe abscesses and foot rot. Differentiating between these two conditions can mean the difference between ineffective treatment, wasted money and performance losses.

 

(Photo credit: Dee Griffin, DVM, MS) Rear view of a typical foot rot, a disease of soft tissues. Note the location and check for odor when investigating.

Toe abscesses
Toe abscesses are a common, significant cause of feedlot lameness that can be difficult to treat if not caught early and can cause performance losses, as well as further injury to cattle resulting in amputated toes, legs and animals being realized for salvage value.

The majority of toe abscesses are typically seen in newly arrived cattle anywhere from 4-14 days post-arrival. At this time, a lot of cattle arrive through sale barns, sorting barns and collection points. “We used to think we were causing them in the processing barn at the feedlot, but when you look at the time frame it takes for an abscess to form after an injury to the sole, it’s usually going to take four to 10 days before the pressure within the claw really starts to show up as a lameness,” says Tom Edwards, DVM, Midwest Feedlot Services, Kearney, Neb.

Brent Meyer, DVM, MS, Four Rivers Feedlot Services, Galva, Iowa, agrees and says toe abscesses tend to occur with 5-10 days on feed, and 7-10 days after re-implant in processing facilities that are not properly designed. “I think type of footing, cattle temperament and cattle handling are the three main components to a toe abscess problem.”

Toe abscesses can be a confusing cause of lameness because they can happen on front or hind feet and in inside and outside claws. Edwards sees most toe abscesses in the outside claw of the hind feet. Dee Griffin, DVM, MS, Great Plains Veterinary Educational Center, Clay Center, Neb., says there’s a propensity for toe abscesses to be in the front claw more than the rear, while Meyer adds that toe abscesses tend to be found on the inside claw on front hooves and outside claw on rear hooves.

Regardless of where it happens, “if you can feel swelling at the coronary band toward the front to the lateral one-third of the foot, you’ve lost the war,” says Griffin. “You now have an infection that’s up into the entire 3rd phalanx and is pushing into the 1st or 2nd phalanx, so you’re into the joint and it’s extremely difficult to recover at that point.”

Several things can contribute to the birth of a toe abscess. Edwards says rainy, wet conditions can soften up the sole, predisposing the foot to having problems. “It can happen if we’ve had a lot of snow and freezing conditions where we have sharp edges on the soil.”

Poor cattle-handling techniques and use of hot shots can cause toe abscesses when flighty or frightened cattle are moved too fast and tend to push off their toes to run or turn. Combine that with flooring that exacerbates sole problems, such as rough concrete or sanded concrete that literally grinds off hooves, and you’re ready for a toe abscess outbreak.

Diagnosis and treatment
Finding a toe abscess is as simple as using pliers and a rope. Securing the foot for a thorough examination is key. Next, applying pressure on the toe with a hoof tester or pliers will let you know if an abscess is working, Griffin says. “If it’s an abscess, it hurts and the animal will flinch or tighten its muscles.”

Meyer also instructs crews to pick up the foot and look for the obvious swelling and spreading between the toes, such as for foot rot. “Toe abscesses won’t swell up early in the process,” he says. “If one waits until the swelling is evident, then treatment response is not rewarding, and toe amputation usually results.” Like Griffin, he instructs crews to use hoof testers to check for pressure discomfort in the toe. “The affected toe will be very painful, and the calf will pull it away immediately.”

If an animal reacts to the pinch of the pliers, Griffin says, “take the nippers, understand where the white line is and cut a perpendicular tip off of that toe. If you get blood, you’ve opened up a site for infection and you’ve gone too far. Just look for a bit or a drop of a chocolate-covered exudate like hemolyzed blood in the middle of the white color.” If this is found, Griffin suggests nipping both toes on both feet. “If I have a pen outbreak, I put a 2-by-12 in the bottom of the chute, use a chisel like a post driver and take off the tips of all eight toes without damaging them.”

Overzealousness in treatment, however, can have bad results. “Every one of us was taught in veterinary school to dig these sole abscesses out and pack them and wrap them,” says Griffin. “These are cattle, and we’re not going to be wrapping their foot every day and putting them in dry stalls on bedding. They are going back in an environment that is not conducive to this. You need to leave an out for the abscess at the toe or it just gets worse. If you dig the bottom of those out, the bones underneath there will literally disintegrate. Once that infection starts up their leg, if it’s front leg, you have the option to amputate the leg at mid-radius and have a three-legged calf, but they are salvage value at best.”

 

(Photo credit: Dee Griffin, DVM, MS) The pencil marks demonstrate the approximate targets for trimming the hoof to relieve toe abscess pressure.

Using antibiotics has to be considered carefully. Griffin says a long-acting antibiotic with good tissue penetration is the best choice, and he suggests a week-long therapy. “Try to minimize hassle and watch them like a hawk,” he says. “Once it’s drained, they should act better. If they are not better in 48 hours, make sure your diagnosis is right.”

 

(Photo credit: Dee Griffin, DVM, MS) This photo demonstrates the damage done when too much claw is removed in a toe abscess case. Note the damage to the 3rd phalanx.

Is nipping toes always the right thing to do? Maybe not, says Meyer. This year, he and his crews used a longer-duration antimicrobial so the cattle didn’t have to be handled as much. He decided not to nip toes because of the excessively wet fall, and the environment the cattle were going into after treatment was not compatible with an open wound. “We haven’t found anything in the literature that indicates treatment response is improved with nipping versus not nipping the toes,” he adds. “In the past, we nipped a lot of toes only to find a dry cavity, not actual pus. Therefore, we wondered if it made sense to leave an open wound. We compared the case fatality rates between nipping toes and not nipping toes this year. We found the case fatality rate was lower in the group in which we did not nip the toes.”

Whether toes are nipped or not, cattle need to have a quiet, clean environment for recovery. “If you have toe abscesses and 6 inches of muddy muck in the home pen, tipping a toe and putting them out there is probably not going to be very friendly for them to recover,” says Edwards. “If you can get them into a dry, bedded pen, the chances for recovery are much greater. In most cases, time is about the only thing that will really get them over their condition, whether it’s out on grass trap, pasture or bedded pen.”

Meyer agrees. “A clean, dry pen with adequate bedding for shock absorption is recommended. The less they have to move to water and feed, the better.”

“Most feedlots have a facility where cattle can get out of the mud and muck and onto dry bedding,” says Griffin. “I think they need at least a week for the contraction and to get ahead of the infection.”

Even a successfully treated toe abscess has an economic impact. Meyer says the treatment cost for a 700-pound steer/heifer that is treated once and returned successfully can cost between $25-$30. “We tend to see a 40-pound reduction in body weight that they never recover. With today’s prices, that can cost the producer an extra $30-$50.” Meyer figures that a treated calf that returns home successfully will cost up to $70 per head, and if it needs retreatment, the loss can be easily $100-$150 per head. “This assumes a 0 percent case fatality rate, which we find is uncommon,” he says. “I would have to assume that there might also be a quality grade reduction in these cattle, similar to cattle treated once for respiratory disease.”

Foot rot
Foot rot is a disease of the soft tissues in the interdigital space, most notable for its unmistakable foul smell. The main cause of foot rot is damage to the interdigital space, which allows Fusobacterium necrophorum to invade. “If you injure the interdigital space, you’ll have literally outbreaks of foot rot,” says Griffin. “The foot rot organism is in every pile of cow manure ever shed. All it takes is an abrasion between the toes to become infected.”

 

(Photo credit: Tom Edwards, DVM) Damage can be done to prescapular lymph nodes when cattle hit their shoulders hard in the chute.

Changes between dry and wet conditions or freeze-thaw conditions can affect the integrity of the interdigital space and predispose the foot to developing foot rot, says Edwards.

Outbreaks can occur if cattle are run in on top of pens that have overgrowth or crusted surfaces. Poorly designed or maintained pens without adequate mounds or with pooling of mud around waterers and in low spots contribute to foot rot problems. Foot rot usually occurs in wetter times of the year. Griffin notes that wet areas in the pen that tend to be muddy and freeze and thaw and get in between claws can cause abrasions.

Meyer also sees the incidence rates increase during freeze-thaw cycles in late fall and early spring, but summertime can also be a problem. “We can see foot rot problems spike in the summer, also with hot days and stable fly problems,” he observes. “The cattle tend to bunch together and stomp their feet to rid themselves of the flies. This causes trauma to the interdigital area leading to an increase in foot rot problems.”

“Basically, foot rot is a pen maintenance issue,” Griffin says. “You can talk about liming a pen to discourage the organism, but the real issue is cleaning the pen. However, if you want to control it during the wet times of the year, pen maintenance starts back in June and July of the previous year.” Griffin likes to use well-seasoned manure (not sand or clay) packed to 100-pounds density, and the loose material scraped off every 30 days.

When Edwards trains crews in pen maintenance to help prevent conditions that favor foot rot, he has found that digital cameras can make the point. “You can take pictures and show them low spots around the waterers, how mounds look, etc., and show them what they need to do to help maintain those pens correctly.”

Foot rot treatment
Griffin says in foot rot outbreaks, cattle respond well to oxytetracycline or chlortetracycline. Sulfa drugs are another good choice but are more expensive. “Cattle respond nicely to therapy to about anything you pick up, and I tend to use a lot of oxytetracycline in individual animals.”

For foot rot, Edwards says it’s common to use an oxytetracycline, Banamine© and sometimes a low dose of dexamethasone to help get the inflammatory response under control. He likes to bring in foot rot cattle, treat them and send them back to their pen the same day. He’s not a fan of putting those easily treated cattle in the hospital pen. “We don’t need to expose the cattle with musculoskeletal problems to pathogenic things going on in the sick pen,” he says. “However, our long-term recovery animals should probably have a pen by themselves.”

Once successfully treated, cattle with foot rot should put on compensatory gain. “Over 10 years of data show that while there is an expense associated with foot rot, you can’t detect it on weight gain,” says Griffin. “They get over it, get into the packing house and it’s indistinguishable in weight gain.”

Lameness-causing injuries
Aside from toe abscesses and foot rot, injuries are a major cause of lameness in cattle, especially in upper limbs, shoulders, hips, etc. “Every time you put cattle in a chute for re-implanting or anything else, the potential exists for stifle injuries, calves will start riding, slip off and hurt the upper leg,” says Griffin. “Handling events always put cattle at risk.”

Edwards notes that a lot of shoulder injuries happen in the chute. “They are a function of the guy running the chute not being cognizant of slowing the animal down with the squeeze before head-catching him,” he says. “Our philosophy is if their back feet come off the ground when you catch their head, that’s a bad thing.” Damage can be done to the prescapular lymph nodes when cattle hit their shoulders hard and create soft tissue damage. Cattle getting caught too late in the chute behind the shoulders, on the ribs or even the hips may not show lameness immediately but in a day or so will be pretty sore.

 

Tom Edwards, DVM, says toe abscess cattle need to recover in a dry, well-bedded place.

Meyer says most shoulder and hip injuries occur within days of processing. The first thing he does when injuries related to facilities are suspected is walk through the processing/hospital/loading areas looking for deficiencies in the system that may be causing the problems. “Most often, one can spot the problem as metal sticking out into the alley, bolts, sharp edges on the floor, etc.,” he says. “You should also observe the crew concerning hotshot usage and squeeze-chute operation. They should always try to catch the calf with the squeeze, not the head gate.”

 

Dee Griffin, DVM, MS, says foot rot is a pen maintenance issue.

Griffin notes that 7-8 percent of cattle pulled after 30 days are cattle with hip lameness, and one in 10 of those injuries is probably associated with bulling or calves romping and playing. “Seldom do those need much treatment,” says Griffin. “We don’t need to treat everything.” One drug that may be overused in these instances is dexamethasone. “Dexamethasone is one of those drugs I hate to see used much, especially early in the feeding period because of its adverse effects on the immune system,” notes Griffin. “The cowboys need to make sure there is nothing wrong with the toe and then just let the animal go back to its pen.”

 

Brent Meyer, DVM, MS, says footing, cattle temperament and handling are three components of toe abscesses.

One infrequent cause of lameness that used to be a larger industry problem before the advent of Beef Quality Assurance is the use of dirty needles and syringes and the infections caused by them. “Now, it’s an infrequent cause of lameness, but it’s devastating when it shows up,” says Griffin. “Much of that has gone by the wayside, especially because we’ve moved injection sites to the neck. But massive, explosive infections can happen as a result, and we still see some occur. Any time we work cattle and I see calves holding their shoulders or necks, I always check to make sure we didn’t cause that through inappropriate needle use.”

Polyarthritis
Other causes of lameness such as Haemophilus somnus and Mycoplasma bovis infections may first show up as respiratory infections, then progress into polyarthritis. Meyer occasionally sees this problem two to three weeks after excessive respiratory morbidity in calves. “They are the back end of a respiratory case,” says Griffin. “I think all of these have a history of respiratory disease, and if you listen to them with a stethoscope, you can hear changes in the lungs of these calves that have polyarthritis.”

Edwards says these calves may have been treated once or twice for a respiratory infection, end up in the chronic pen and two to three weeks later have major swelling in the knee, hock or hip. Calves with polyarthritis typically look sore and have swollen joints. “Polyarthritis is a tough one to deal with,” says Griffin. “When it rears its head, it beats us alive. Fortunately, we don’t see an awful lot of it. These conditions don’t respond well to therapy, and you’re fortunate if it’s just one or two in a pen. A pen outbreak is bad news.” 

Griffin says he’s compelled to use the best antibiotic he can that has the ability to penetrate the joints. “I keep the steroids away from them, but by and large, you want to get them off drugs and get them out. I will almost always try to treat them one time but just don’t have much success.”

Lame Pen Versus Hospital Pen

All lame cattle are not the same, and some veterinarians believe post-treatment shouldn’t be the same, either. Tom Edwards, DVM, believes that 75 percent of the recovery is in how the lame animal is handled after it’s been identified and treated. “They typically don’t want to stand and walk, and they are going to lay down a lot more,” he says. “In the case of toe abscesses, we’ll try to bed those down with sawdust, wood chips, stalk bales or anything we can get down for them to be able to alleviate the pressure they are going to put on hips and other joints when they lay down. That’s a big factor in how well they are going to recover from lameness. We want to try to keep them off of the concrete pens to avoid ‘concrete toxicity,’ meaning hard surfaces, which are not conducive to recovery.”

Edwards also does not like to see lame cattle put into hospital pens with sick cattle. “We don’t need to expose them to any more respiratory pathogens than we have to. They should be separated, but if you can’t, you’ll expose them to more respiratory pathogens and increase their chances of getting sick.”

Diagnose The Right Thing

One reason lameness can have a severe economic impact is that a misdiagnosis can lead to wasting time, treatments and performance. “If you misdiagnose a lameness that has to do with the toe and improperly treat it, you’ve got an economically bad situation,” says Dee Griffin, DVM, MS. “It starts with a thorough examination. Not everything is a foot rot. If you pick up the foot and put your finger in the interdigital space and there is no foul foot rot smell or lesions, you don’t need to be treating for foot rot. Then it’s time to get a hose, brush it out, hold the foot out and look at the area of the tip of the toe and the white line and consider something else.”

Griffin had his feedlot crew rig up a light next to the chute so that when a calf’s foot was restrained, they could more closely examine it. They are also encouraged to turn the animal out and watch it walk and see where it’s sore. He notes that cowboys need to bring these cases to the attention of the veterinarian when he or she visits.

“A lot of times we have what we call our non-responding lames, and it’s because we don’t understand the cause,” says Tom Edwards, DVM. “If you have a nail or a sharp object stuck between the toes or in the sole, continued therapy with antibiotics or anti-inflammatories is not going to cure that.” Most cowboys can recognize foot rot due to the spread toes, but for those cases with no swelling that are difficult to identify, Edwards says crews need to lift the foot up, look between the toes, feel for any heat
or identify the pain situation. “Without identifying those types of things, it’ll be difficult for you to get the response you’re looking for.”

“You always need to check for foreign objects, such as nails, wire, etc., when checking lower leg lameness,” adds Brent Meyer, DVM, MS. “When we rule out foot rot and toe abscesses, we then investigate problems further up the leg, such as arthritis and injury.”

Meyer points out the clinical differences between foot rot, toe abscesses, trauma, broken legs, corns, laminitis, etc. “We also have specific treatment protocols for each condition so we can better address successful treatment options.”

Which leg is lame?

Sometimes looking at a lame animal and figuring out which leg is lame is the hardest part of the diagnosis. A thorough examination, which often includes a foot exam within a restraining chute, is the best method of determining a questionable lameness. But before getting an animal into the chute, a simple way to determine which leg is affected is to observe the animal in motion, says Edwards.

Typically, the stride of the animal will be affected, which causes it to compensate weight-bearing load on the affected limb. To accomplish this, the animal will perform a “head bob” to redistribute the weight. “In the case of a front-limb lameness, as the affected foot strikes the ground, the animal will bob its head up in an attempt to decrease the weight-bearing load. With respect to hind limb lameness, the animal will throw its head down to redistribute the weight-bearing load.”

In early and subtle lameness, the head bob can be difficult to see at a walk but may be more noticeable at a trot. Other signs to look for are how they mechanically move the limb – shoulder, stifle or hip injury will present with a different mechanical stride. They usually “swing” the affected limb to accomplish the stride, while lower limb lameness may not affect the overall phase of the stride but how they place the foot on the ground.

As for toe abscess lameness, there is little or no swelling observed, but if the outside claw on the hind limb is the culprit, the animal will usually turn the leg laterally (outward) to place the weight on the inside claw. “This can be misleading to the observer, because the hip will also turn outward and give the impression that the location of the lameness is high, such as in the stifle or hip,” says Edwards.

Griffin adds that toe abscess cattle will also walk heel first. “It can be frustrating to try to figure out which leg it is in some lameness cases,” he says. “If you have the cowboy almost duplicate in their own walk what the calf is doing, they can figure out which leg, toe, heel or knee it is. It’s the same thing as figuring out what is wrong with their horse. This can be a wonderful opportunity for education.”


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