Foot Rot in Cattle

Also known as

Interdigital necrobacillosis, foul foot

Description

Foot rot is an infectious condition that causes swelling, heat and inflammation in the foot, resulting in severe lameness in cattle. Swelling and lameness usually appear suddenly; one day the animal is fine, and the next day the foot is so sore the animal won’t put weight on it. Cattle lose weight swiftly if they are so lame they won’t travel to feed and water.

The infection requires an opening in the skin between the toes or at the heels and cases occur more often in wet, boggy conditions. When skin is constantly wet, it becomes softer and more easily scraped and traumatized.

Sometimes a person assumes the animal has foot rot because it is suddenly lame. Always examine the foot and make sure of the cause. Sudden three-legged lameness is a classic sign of foot rot, but could also be due to fracture, snakebite, puncture in the bottom of the foot, abscess, or some other type of infection.

Cattle with a rock or stick jammed between the toes, can also be reluctant to put weight on the foot.

Swelling of the foot/lower leg may be due to snakebite or other injury, but in some cases of foot rot the swelling also travels up the limb because of inflammation. Snakebite usually shows fang marks--which may be draining after infection sets it. By contrast, any oozing drainage from foot rot is generally between the toes, with a very foul odor.

Signs

• Severe lameness
• Swelling between the claws or at the heel
• Heat in the foot
• Foul odor
• Drainage from lesion
• Moderate fever (103 to 104 degrees)
• Drop in milk production
• Temporary infertility in bulls following fever

Causes

The bacteria associated with foot rot are mainly anaerobes, which means they thrive in an environment without oxygen. The most common one causing foot rot is Fusobacterium necrophorum. There are often one or more of several other anaerobic bacteria associated with it, however, including Prevotella and Porphyromonas. These are all gram negative anaerobes.

There may also be another pathogen that used to be called Arcanobacterium pyogenes and now called Truperella pyogenes. It forms pus and helps create an anaerobic environment for the other bacteria by reducing oxygen in the tissues.

Sometimes Dichlobacter nodosus is also found; this is the primary bacterium involved with interdigital dermatitis. This anaerobic bacterium and Fusobacterium necrophorum are symbiotic in that they may work together. One of them enters the break in the skin and then the other one comes along and helps perpetuate the infection.  

The bacteria that get started in the area begin to multiply and cause further death and destruction of tissue. This leads to more anaerobic conditions as the tissue dies, which helps facilitate the infection.

Many of these bacteria are normally found in feces, so they are common wherever cattle are located. The animals are always exposed to these pathogens, so there must be an irritation or break in the skin—in the space between the toes. Since cattle are walking through feces, anything that disrupts the skin on the foot may provide an opening.

Once the bacteria are introduced, it takes about 5 to 7 days for the lesion and lameness to appear. It takes a few days for those bacteria to set up the anaerobic conditions they need in order to multiply rapidly and secrete toxins that cause tissue damage—and then the animal goes suddenly lame. Pain and lameness is due to the necrotic lesion and inflammation—with immune responses that create inflammation and swelling.

There are more cases some years than others; there may be variation in the strain of bacteria (some may become more pathogenic), but the varying incidence of disease may be related to environmental factors. Feet become soft and more easily punctured, scratched or bruised if footing is wet or muddy.

If it’s hot and humid after a period of rain, cattle may be congregating under shade trees where they defecate and urinate and their feet are wet. The hoof tissue starts to break down.

Some cases occur when cattle are out on stubble (such as harvested grain fields) that may poke between their toes. Walking on gravel, sharp ice or any other sharp or abrasive surfaces may also create nicks and abrasions.

Once there have been a few cases, bacteria may be spread more (from draining lesions) with higher concentration in the environment. This tends to amplify the number of cases.

Prevention

Eliminating mud as much as possible, and reducing risks for trauma to the feet are the main prevention strategies.

In a feed yard, handle cattle with the least stress possible, so they are not scraping their toes on concrete or getting abrasions on the sides of their feet by being jammed and struggling in alleyways. Wood chips can improve the footing in facilities where there might be potential for trauma to the feet. Keep pens clean, removing mud and manure. Mounds where cattle can get up out of the mud can make a difference in helping keep the feet healthy.

Some of the management things that can be done when cattle are out on pasture are make sure they are rotated around so they are not always congregating under the same trees. If you move them to different areas there won’t be as much buildup of manure where they are standing and bedding. Even moving the feeders, mineral tubs, etc. can help, so cattle are not constantly at the same places. This helps spread out those wet areas.

Select cattle with good feet and leg structure. Good husbandry practices and genetic selection in the right direction for foot and leg structure, are key factors, along with good nutrition to keep the immune system, skin and feet healthy. A good mineral program is essential.

The biggest issues are selenium, copper and zinc deficiencies—all of which are needed by the immune system in proper balance, to function correctly. Zinc and copper are especially important for foot health.

Zinc is one of the trace minerals important for hoof horn growth. Research has shown decreased incidence of foot rot with zinc added to the diet. Zinc has been shown to help with skin and hoof health/integrity.

It also helps to isolate any animal that gets foot rot. Bring it in and treat it, and keep it separate until the infection resolves, so it won’t be spreading bacteria for other cattle to pick up. Once you see a case, be vigilant to pick out any new ones and isolate them. The earlier you can treat them, the better.

There is a vaccine against Fusobacterium necrophorum as a preventative against liver abscesses and foot rot in feedlot cattle. Feedlots that use the vaccine to try to limit the incidence of liver abscesses generally see a reduced incidence of foot rot. There are at least a couple vaccines that include Fusobacterium. Vaccination may help reduce foot rot problems but won’t eliminate them.

Treatment

Foot rot responds quickly (with complete recovery in a day or two) if broad-spectrum systemic antibiotics are given soon after the animal is discovered to be lame. Always examine the foot before you give antibiotics, however, in case the lameness is caused by something else. If the animal is in a chute for treatment, lift the foot with a rope to look at the bottom. If you rope the animal out on pasture, it can be cast on the ground for treatment and closer examination of the affected foot.

Several systemic products are labeled for foot rot including Nuflor, Exenel, Naxcel, Draxxin, LA-200, and penicillin. The organisms that cause foot rot are very responsive to antibiotics. Most people still use long-acting oxytetracycline or Procaine penicillin because they are cheaper. LA-200 (oxytetracycline) has been the traditional treatment and has the right spectrum for these bacteria.

The only downside is that you only get about 48 to 72 hours of therapeutic drug levels in the animal, so it may require a second treatment. But LA-200 is an economical and effective choice, especially if you catch it early. This is the key—catching a case of foot rot early, treating with the proper antibiotic, and putting the animal where it’s clean and dry.

Excede (ceftiofur) has a 7-day tissue level--a longer duration of activity with just one treatment. This is helpful when treating cattle that may be harder to access again, such as out on pasture. Excede is more expensive, so people tend to use this drug when the animal’s value is higher, or the condition is more severe, or when they don’t think they will have another opportunity to treat that animal.

Some people add Banamine to the treatment protocol because it helps decrease swelling and inflammation. If pain is reduced, the animal may get up and move around more—going to feed and water. Banamine is not labeled for treatment of foot rot, however, so this would have to be prescribed by your veterinarian as an extra-label use.

Local treatment of the foot is also helpful. The foot can be lifted up, and a strip of rolled up gauze soaked with Betadine can be used to floss the area between the toes. This clears away buildup of dead tissue, opens it up for air to get to it, which inhibits bacteria that love anaerobic conditions.

Systemic antibiotics generally work very well if you catch it early, but if the infection is longstanding, you may have to clean up the foot (floss between the toes with a piece of gauze, clean rope, twine or towel to remove the necrotic tissue) and apply a topical antibiotic such as oxytetracycline.

Putting LA-200 on a gauze pad and wrapping the foot to hold it next to the affected area may help. This will also decrease shedding of bacteria into the environment.

If the animal is not greatly improved (no longer lame) within 3 to 4 days after antibiotic treatment, there may be some other cause of infection and lameness or it may have gone into deeper tissues. If foot rot has been going on for awhile, it may be harder to clear up.

Some cattle get over the lameness within a few days without treatment, but others get worse if they are not treated. It depends on the immune status of the animal and how much of the bacteria actually got in there initially, and how quickly the immune response can stop the proliferation.

If treatment is delayed and the infection gets worse, it will take a longer course of treatment. Most drugs, given systemically, have trouble getting into the middle of those lesions because necrotic tissue does not have much blood supply.

That’s when you need to clean out the lesion and treat topically. If you can rid of the debris between the toes and use a topical antibiotic on the lesion it may respond better.

If neglected too long, a severe infection may expand into the joint and cause permanent damage. This can be a serious issue, especially in a big bull or any heavy animal. It’s much better to treat it promptly and get it cleared up before it goes that far.

If it has gone deeper, damaging the bone or joint, there are surgical options which include removing all the dead tissue and cleaning it up so it can heal. Toe amputation is the most drastic measure, if the infection has affected the ligaments and bones.  Once these structures are damaged, systemic antibiotics are rarely helpful.

In a steer or a cull cow with bone involvement that you are trying to get to market, the veterinarian may try to salvage the animal by removing the affected toe. This would allow the animal time to heal and be comfortable enough to make it to market. This isn’t a long-term fix, but might allow the animal to regain lost weight and recover enough to be sold or butchered.

Some of the chronic cases that are hard to clear up may be caused by what some people are calling super foot rot—bacteria that are resistant to antibiotic treatment. These are very difficult to treat and you need to work with your veterinarian. Together you could decide if you want to try a salvage procedure such as toe removal or whether the animal is beyond treatment.

The cases that get into the bone or joint may be caused by the super foot rot bugs that don’t seem to respond to antibiotics, or cases that were neglected and longstanding because the producer didn’t see the animal earlier in the disease.

Bacteria may continue to invade the deeper tissues and get into the joint. By that time the animal usually has lost a lot of weight because it hasn’t been traveling.

If surgery is performed to remove a damaged claw, the animal will be impaired and unable to travel very well. It would not be able to continue a typical life. If the animal has high value and genetic merit, however, it could be confined and manage to do all right. 

This might be the case with a valuable cow in an embryo flush program, or a bull that could be collected for AI breeding. They are not required to travel like a commercial cow would have to do. These situations are addressed on a case-by-case basis, depending on what the owner might want to try, though the success rates are obviously lower.