Herd HEALTH

The main one we deal with is high incidence of foot rot. On Fusobacterium necrophorum,” he says. the other hand, husbandry and These bacteria are almost environmental management always present in the environment. is a big part of the picture. If Signs of foot rot include swelling environmental issues are causing at the heel or between the claws, the problem, I would try to and the swelling sometimes breaks change those things. The vaccine open and drains. can be a good tool, but should be “The biggest thing in looked at as just one part of the preventing foot rot is managing total management.” the environment to reduce For treatment, he advises risks for foot rot. This means using an antibiotic with the eliminating mud as much as proper spectrum and durability possible, and reducing risks for of activity labeled for foot rot. trauma to the feet especially “LA-200 is an economical and between the toes. Rocky or frozen effective choice, especially if you conditions in which the skin may catch it early,” he says. be broken by sharp rocks or ice This is the key — catching it can predispose cattle to foot rot,” early, treating with the proper Raymond says. antibiotic and putting the animal “In the feed yard, we try where it’s clean and dry. to handle cattle with the least “Another antibiotic I often use amount of stress possible so they for foot rot is Excede. This factor are not scraping their toes on has a seven-day tissue level. We get concrete or getting abrasions on a longer duration of activity with the sides of their feet by being just one treatment. This is helpful jammed and struggling in the when treating cattle that may be alleyways,” Raymond explains. harder to access for additional “We use wood chips sometimes treatment, such as out on pasture. to improve the footing, and Excede is more expensive, so I use minimize any areas where there this drug when the animal’s value might be potential for trauma to is higher, or the condition is more the feet. We do everything we severe, or when I don’t think I’ll can to avoid muddy conditions, have another opportunity to treat keeping pen space as clean as we that animal,” Raymond says. can. This is a challenge in the There are some complications winter, but we remove mud and that can occur with foot rot. manure as quickly as possible.” In long-standing cases the Out in pastures, boggy infection may get into the joints, conditions should be addressed, and the animal may develop if possible. septic arthritis or cellulitis if the “We also try to select for cattle with good feet and leg structure. Just as in other diseases, there is a genetic predisposition for Hoof disease resistance. Some cattle have stronger immune response than others, and I don’t think foot rot is any different, but good foot and leg structure is also crucial,” he says. “Good husbandry practices Health and genetic selection that takes us the right direction in foot and leg structure are key factors, along Identify common foot problems with good nutrition to keep the and treat them accordingly. immune system, skin and feet healthy. A good mineral program is crucial for keeping the immune by Heather Smith Thomas system healthy. Our biggest issues here are selenium, copper and “The biggest thing zinc deficiencies — all of which are needed by the immune system in in preventing foot attle sometimes suffer foot probably because we’ve had a lot order to function correctly. Zinc rot is managing injuries or diseases, and of moisture,” Reppert says. “This and copper are also important to Ca lame animal may lose spring and summer stockmen foot health,” he explains. the environment weight if it spends most of its time are having more cases of foot There is a vaccine for foot lying down rather than grazing or rot than they ordinarily do.” rot. “We haven’t used it in our to reduce risks for going to feed or water. Moisture softens up the skin operation, but the literature on it foot rot. This means Assistant professor at Kansas and feet, and these tissues are is encouraging. One of the herds State University’s College of more readily nicked or scraped, I work with in our area has used eliminating mud as Veterinary Medicine and DVM, opening the way for pathogens it a lot and the owner feels like much as possible, MS, DACVIM Emily Reppert says that cause foot rot. it has reduced their incidence of environment can play a role in Director of research and foot rot. They are now treating and reducing risks hoof health — whether the weather veterinary services at Simplot only one or maybe no cases of for trauma to the feet and pastures are wet or dry. Livestock Co. Randall Raymond foot rot per year, compared with says foot rot can be caused by an average of about 20 cases per especially between Foot rot two different bacteria. “These year before they started using the the toes.” “This year, here in the Midwest, are opportunistic pathogens that vaccine,” says Raymond. we’ve been dealing with more require some trauma or break in “The vaccine would be worth — Randall Raymond foot rot than other years, the skin to enter the foot. looking at, if a person has a

56 / August 2015 Hereford.org infection gets into the tendon similar to those of dairy cattle,” sheath. “If these complications Reppert says. occur we may do additional Strawberry foot rot/hairy heel treatments,” he explains. warts is caused by a spirochete If the infection gets into the bacterium, according to Matt joint or tendon sheath, generally Miesner, DVM, MS, DACVIM, the animal has to be culled. and clinical associate professor “In seedstock animals with at the K-State College of high individual value that won’t be Veterinary Medicine. entering the food chain, we may “It is not necessarily between do joint flushes. It’s rare that we’d the toes but more in either have to get this aggressive, however, the front cleft or the back cleft because hopefully the producer between the heel bulbs,” Miesner noticed the condition and treated says. “It appears as a reddened, it before it gets to this point,” roughened, ulcerated, irritated Raymond says. area. It looks granular, like a Cattle out on range, however, strawberry, and is very painful. In Foot rot causes painful swelling between the toes. may not be seen often enough for other stages it may have long hair- the producer to know when the like structures that grow out from being fed a lot of concentrate they may also develop an abscess problem started. In some of these the heel. This would be something feeds like bulls on test, show in the crack if it is very deep,” animals, there may be extensive to check for if the animal is very animals that are pushed hard Reppert explains. “These animals damage by the time they are lame, before you assume that you nutritionally, and during times need a hoof trim, to get the toe brought in for treatment. are just treating a routine foot rot.” of year when there is a lot of as short as possible and relieve “In those cases, there may be Miesner adds, “I’ve seen this moisture as well.” pressure on the hoof wall.” no treatment that will completely condition in bulls that are housed The earlier cattlemen discover Professor and extension cure the problem. We try to get in groups or cattle confined in a a foot problem, the better. If it’s veterinarian at Iowa State the cow through that season, to feedlot situation. This disease is white line disease, it needs to University Jan Shearer says vertical wean her calf, and market her diagnosed with a biopsy of the be cleaned out and treated like wall cracks are more common in later,” he says. “Those that we lesion; the bacteria can be seen an abscess. “A good foot trim beef cattle than dairy cattle, but catch early and treat appropriately under a microscope.” can help eliminate some of that horizontal cracks are common probably have about a 90% success Treatment is different than soft white line and detect any in all cattle. These cracks run rate, if it’s truly foot rot.” for foot rot. “This disease does infection,” Reppert says. “At that parallel to the coronary band If surgery has to be performed not respond as well to systemic point a good foot trimmer or and often represent a benign in a severe case to remove a antibiotics. We usually use a veterinarian would be able to physiological change that creates damaged claw, the animal will formalin foot baths, thoroughly identify soft spots or any manure mild disruption of hoof horn be impaired and unable to travel rinsing the feet--an intensive and debris that is packing in formation. They can result in normally. “If the animal has high program to try to halt the along the white line. Those could severe lameness, however, if they value and genetic merit, however, infection. We may also use a be pared out. A large part of are deep. it could be confined and manage topical oxytetracycline spray, treatment in many cases will be to Rings around the hoof are to do all right. This might be and try to dry the foot. Moisture alter the diet a little, and change common because the hoof the case with a valuable cow in allows these bacteria to keep the environment.” wall grows at different rates an embryo flush program, or going,” he explains. Many hoof problems, with the during various seasons and a bull that could be collected There are vaccines for exception of things like foot rot also for physiological reasons, for artificial insemination (AI) strawberry foot rot, and these are or an abscess caused by infection, creating growth rings which may breeding. We address these on a sometimes used in dairy cattle are usually not a quick fix. “It may occasionally become cracks. case-by-case basis, depending on or in bulls that are housed in take several months before you “Every time the cow calves what the owner might want to try. preparation for sales. “Whenever see a response to your changes/ she goes through a period where In these cases the success rates are there are housed animals in a treatments, especially something hoof wall growth slows greatly or obviously lower,” he says. wet, moist environment there is a like white line disease where you stops, due to a major physiological chance for this type of infection have to change the nutrition,” change affected by her hormones Interdigital dermatitis and it is very contagious. It needs Reppert says. and metabolism as she goes from a and heel warts a little help with moisture and non-lactating to a lactating stage,” “Another thing we are seeing disruption of the foot but it can Hoof cracks Shearer explains. “There’s an in conjunction with increase get started pretty quickly and is Hoof cracks will also take time interruption of hoof horn growth in moisture here this year is much harder to treat than foot to correct, since the hoof has that creates a horizontal groove, interdigital dermatitis,” Reppert rot,” he says. to grow out in order to regrow or a growth arrest line — which is says. “This is probably more “If a lame animal has a lesion healthy horn. “I hesitate to say associated with calving,” he says. common in dairy cattle because of between the toes or heel bulbs that sometimes the tendency to If a cow has horns, this same the way they are housed, but we that looks like foot rot but is not cracking is hereditary because we change occurs in horn growth. are also seeing some cases in beef responding to antibiotics, a closer don’t really know, but it seems like “The rings on her horns signify cattle. This is not the same thing look may reveal its true nature,” conformation and genetics does when each calf was born. If a as heel warts, but is another kind Miesner says. play a role,” Reppert says. cow has had eight calves, there of dermatitis or inflammation of “Some people believe that the continued on page 58... the skin around the heel — often White line disease so-called sand cracks are due to associated with too much moisture. “Something we see in all regions sandy soil that gets into grooves of It can be painful, and might be of the country is white line the hoof and works its way in and confused with hairy heel warts disease,” Reppert says. “It may starts the cracking. Often we see which is contagious and would be be partly due to environment vertical wall cracks in the animals a much more significant problem if such as increased moisture, that have a really long toe. When identified on the property.” which leads to softening of the the toes are overgrown it puts With beef cattle there’s a white line, but there is also a more strain and pressure on the wide spectrum of environmental nutritional component. The vertical hoof wall, and with this conditions, from herds on dry hoof tissue becomes very soft at kind of stress there is more risk pastures in the mountains or desert the white line, the area where for cracking,” she says. rangeland, to cattle on irrigated the sole meets the hoof wall, Cracks are a perfect place for pasture, to cattle in confinement in and this predisposes the foot to manure and debris to pack in. “It’s feedlots or on feed tests or being development of abscesses. Manure not uncommon to have an animal prepared for the show ring. and dirt gets packed up in there.” lame, not only because of the “Some of these are confined Reppert explains, “We see it packed debris putting pressure on Pictured is an example of a full-length vertical crack. and housed and might have issues most commonly when cattle are the sensitive part of the hoof, but

Hereford.org August 2015 / 57 Herd HEALTH ...Hoof Health continued from page 57 will be eight rings on her horn. formation create distinct ridges She doesn’t get an annual ring; and grooves. the change occurs with calving,” “In the most extreme cases Shearer says. These growth rings where the fissure is deep enough are consistently found in both to create a full thickness defect beef and dairy cattle. in the wall, this lesion is called a Seasonal changes are another thimble,” Shearer says. factor in hoof growth rate. This When a deep crack gets down factor may be partly nutritional to the level of the corium, the (time of year when feed is more sensitive “quick” underneath, it plentiful, with green grass) or goes all the way through the horn. due to longer hours of daylight. “The fragment below the crack “Growth rate is affected by may become separated from the physiological factors and may hoof wall above it. As it grows not have as much to do with down the foot and wears away, a availability of nutrients as it does deep crack may become painful with number of hours of daylight. because every time that fragment Horizontal cracks can create what are called “thimbles,” separating from the rest of the hoof. Some of these things are not well moves, it pinches the underlying understood, but people need to corium tissues,” Shearer says. steeper angle than the hind foot treatment. But if cracks cause realize that not all horizontal Vertical cracks are often called and are thus subjected to more lameness, they can be complicated rings are indicative of disease,” sandcracks. “Less than 1% of dairy stress,” he says. Beef cattle travel to manage — especially the vertical he explains. cows develop vertical wall cracks, on earthen surfaces (and rocks, wall cracks,” he says. “Some rings are associated but up to 64.5% of beef cows get and often very rough terrain), and “If the foot is overlong, we trim with disease situations or vertical cracks. More than 80%, of in some cases, the feet may be it back, and sometimes we can extreme changes in nutrient level these cracks occur on the outside drying out too much. remove the fragment, or a portion or balance or availability. We claw of a front foot. The front “But dairy cows are standing of it, by trimming. Sometimes we sometimes see an extremely deep feet carry a more weight than on concrete all day and rarely can trim it enough that it won’t horizontal groove — and we tend the hind feet. The inside claw is get vertical cracks. Based on be flexing so much. Depending to associate this with something slightly larger, and bears most of the numbers, there seems to be on how far down the foot it is, beyond the normal physiological the weight,” Shearer says, but there a breed predisposition to wall sometimes trimming alone can changes, such as disease,” he says. may be more movement and strain cracks,” he says. Some family provide some relief until the foot When hoof horn formation on the outer claw. lines, in any breed, also have more can grow out. It’s the movement resumes, a full-thickness crack “Some people have thought tendency to cracking. In a certain and pinching that causes pain.” sometimes develops. These that cracks are related to dryness, herd, often the cows that develop severe disruptions in hoof horn or the fact that front feet have a vertical wall cracks are related. Injuries “Other factors associated with “There are also occasional vertical cracks include vitamin traumatic injuries to the foot. In An accurate diagnosis and trace mineral deficiencies. this part of the country sometimes Some people have suggested that we have flint rocks that migrate Many lame animals are simply assumed to have foot rot, but it’s wise to have a proper diagnosis. laminitis may play a role. Some through the hoof and damage “If you think the animal has foot rot, and you treat it with an antibiotic that is ordinarily very of the reasons remain unknown, inner tissues,” Reppert says. effective against foot rot, and it is still lame, you should have that animal evaluated,” says however,” Shearer says. “Thorns from a variety of trees Emily Reppert, DVM, MS, DACVIM and assistant professor at Kansas State University’s College “Body condition may be can also become a penetrating of Veterinary Medicine. a predisposing factor; heavy, foreign body. Often those animals “Either it has a super-resistant pathogen causing the infection, or it is not foot rot. If it’s overweight cattle may be more are lame but don’t have a lot something else, it may be something significant that needs attention. It is crucial to have an at risk. Age may also be a factor, of swelling, unless it gets into accurate diagnosis, as early as possible,” she says. since older cattle tend to have the joint. They are very lame Once what is actually going on with the foot is understood, the problem can be treated more sand cracks. Selenium, either but generally don’t respond to properly. “The joint capsule and joint space are very close to the hoof wall, in the bovine hoof. too much or too little, can have antibiotic treatment.” Any unresolved infection in one part of the hoof can rapidly lead to infection in the joint. These an adverse effect on hoof wall If there is something stuck in complications, though not always career-ending, are definitely more serious than simple foot rot,” strength and growth. There are the foot, like a thorn or a nail, the she says. many possible causes for cracks,” foot should be examined and the Swelling and lameness may be due to a snakebite, puncture wound, sole abscess, sprain or he says. object found and removed. fracture, or some other injury. It is always wise to restrain the animal and examine the foot — To treat a crack, sometimes the Freak accidents can also especially the bottom of the foot — to make sure it’s not a sole abscess or a nail in the foot. If it’s affected animal’s movement needs damage the foot, like getting the something besides foot rot, it may need additional treatment and not just antibiotics. to be limited so it doesn’t have to hoof caught in a cattle guard, chute, tilt table, etc. A caught Sometimes even a simple foot rot that is neglected and not treated may end up resulting in walk very far to feed and water. “If one side of the foot is a little better hoof may end up with the hoof extensive infection that may end up in the joint. Lameness should not be neglected. Its cause than the other, we may try to thin horn pulled/sliced off on one or should be discovered and the problem should be treated appropriately. HW the horn or stabilize it in some way, both toes. “I’ve dealt with that and take the weight off the claw on multiple occasions,” Reppert where the fragment is less stable. says. The animal has to grow We may glue or nail a wood block a new horn shell but you may under the healthy claw, to leave need to keep the foot clean and the cracked claw off the ground bandaged to protect it while the so it doesn’t bear weight. If we get new horn grows. the weight off, the corium won’t “All the important internal continue to be traumatized, and will structures of the foot are close hopefully heal and start to produce together, so if one gets infected, new horn. Once it does that, it will often the others do, as well,” self-correct,” Shearer says. Reppert says. A calf with a lost “The main objectives in therapy horn shell is easier to deal with and are to stabilize the two portions treat than a heavy adult that has to of the wall that are loose and put a lot of weight on the foot. moving or pinching. Sometimes “Here at the university we have the two fragments can be wired the luxury of having a tilt chute together, or stabilized by other where we can lie the animal down means, including surgeries. Only a for treatment. It’s more difficult small percent of hoof wall cracks if you have to lift the foot up to actually cause lameness and need clean and treat it.” HW

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