In the last issue we discussed pinkeye as a major cause of disease in cattle during the summer months. Another problem that frequently presents itself in my chute during the summer is foot rot. I have seen numerous cases of foot rot in cattle this summer already. The disease is caused primarily by a bacterium called Fusobacterium necrophorum and is a significant cause of lameness in cattle – beef and dairy alike. Like pinkeye, mortality from the disease is generally absent but morbidity can get high with up to 25 percent of the herd affected in severe outbreaks. Foot rot can be a significant source of lost production. Cows that are lame from foot rot tend to lie around, eat less and produce less milk. Whether that milk is going into the bulk tank or into the calf, less milk means less money to the producer. Additionally, treatment costs and the occasional animal with unresolving lameness represent further economic loss due to the disease.
Southwest Missouri is notorious for hot, humid summers and that creates an excellent environment for the foot rot organism. Cattle out on wet ground or constantly walking through wet grass are at a greater risk of developing abrasions of the skin around the foot giving the organism opportunity to set up infection. Typically, a lesion develops in between the toes, the foot swells and lameness appears suddenly and generally affects only one foot. Many animals will recover without treatment but lameness will typically persist for weeks and the risk for joint involvement increases. In certain cases, if the disease is not treated effectively and infection does spread to local joints, recovery becomes much more difficult and prolonged. This will be indicated by swelling that begins to climb up the affected leg. If joint involvement does occur your typical antibiotic injections are rarely effective and surgical draining of the joint is often necessary with extensive foot soaking and antibiotic therapy to follow.
Discharge from the feet of affected cattle is considered the source of transmission. However, the organism can survive for a month to several months in the environment allowing for future outbreaks.
Prior to treatment, foot rot should be distinguished from other causes of lameness. The foot should be cleaned and examined. If foot rot is indeed the diagnosis, prompt treatment with systemic antibiotics such as LA-200, penicillin G or others as prescribed by your veterinarian will often result in a quick recovery. Typically, prevention is centered on avoiding abrasions to the feet by minimizing time cattle spend on rough ground such as dried mud, rocky corrals and coarse, bush hogged weeds etc. Additionally, reducing exposure to wet ground and providing a good mineral supplement (specifically supplementing zinc and organic iodine) may also help to reduce case numbers. A vaccine has been developed but seems to have produced mixed results and has not been definitively proven to be efficacious in the prevention of the disease.
I suggest focusing your efforts on improving environmental conditions and treating cattle early in the course of disease.
Darren Loula, DVM, is a large animal veterinarian at Fair Grove Vet Service in Fair Grove, Mo.
