Barry Whitworth, DVM, Senior Extension Specialist, Dept. of Animal and Food Sciences, OSU The long-range forecast found at the Mesonet (https:// www.mesonet.org) predicts above normal chances for precipitation over the next few weeks for most of the state. Many areas in Oklahoma have received much needed rain in the past few days. With moist conditions, producers should be observing their cattle for foot rot.
Foot rot is caused by Fusobacterium necrophorum subspecies necrophorum and sometimes other bacteria are involved (Porphyromonas levii, Prevotella intermedia, Staphylococcus aureus, Escherichia coli and Truperella pyogenes). These bacteria are normal inhabitants of the digestive tract of cattle and consequently in the environment. The problem arises when the bacteria enter the tissue of the foot through a break in the skin. The damage to the skin may be from puncture wounds or abrasions or continuous exposure to wet conditions which softens the skin. Once the bacteria gains entry into the tissue, it multiplies and releases toxins that damage tissue. If left unchecked, the bacteria invade deeper structures in the foot. This may result in permanent problems and may shorten the life of the cow.
Diagnosis of foot rot begins with a thorough examination of the foot. Foot rot lesions usually infect both claws, so if only one claw is infected, the problem is not likely foot rot. Producers should look for signs of swelling between the toes as well as redness or necrotic tissue. Also, observe for separation of the skin at the hoof wall. Most cases of foot rot will have a foul spelling odor. The foot may feel warm to the touch. This distinguishes foot rot from fescue foot which is cold to the touch. Cows may have a fever and refuse to eat. Most cows are reluctant to bear weight on the infected foot due to pain.
When treated early, most cases respond well. Treatment begins with cleaning the foot and removing as much necrotic tissue as possible before applying a topical medication. Most cases do not require bandaging. Administering an antibiotic is also necessary. A producer should consult with their veterinarian for what product works best in their area. Pain management may also be necessary in some cases. Sometimes damage to deeper structures of the foot occur and require more aggressive therapy such as surgical intervention to salvage the animal.
There is a very aggressive form of foot rot with a fast onset, extreme necrosis, and erosion of the interdigital space. The condition is referred to as “super foot rot”. This condition is resistant to regular treatments. Super foot rot is thought to be caused by a resistant strain of Fusobacterium.
Prevention is the best plan of action and begins with good hygiene. Preventing cattle from standing in wet manure infested areas will help detour foot rot. Cows that have foot rot should always be isolated until healed. In the past, the use of ethylenediamine dihydriodide (EDDI) was used to prevent foot rot. However, under the US Food and Drug Compliance Policy Guide, the use of this product is restricted. Also, under the Veterinary Feed Directive (VFD), chlortetracycline (CTC) cannot be added to feed for the prevention or treatment of foot rot since VFD drugs cannot be used in an extra-labeled manner. If cattle are deficient in zinc, the addition of a mineral mix with zinc may aid in prevention of foot rot. Footbaths work well in confinement operations but are not practical in range conditions. There is a foot rot vaccine available with a label claim to aid in preventing disease.
For additional information please contact Greg Hartman, Beckham County Ag/4-H/CED at 580-928-2139.
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