By Mike Neary, Extension Sheep Specialist: Purdue
(reprinted with permission from July/August 1993 The Working Border Collie)
Foot rot in the ewe flock is a frustrating situation. Anyone who has fought foot rot can attest to this. Seldom is the battle completely won. Foot rot always seems to win a partial victory, whether through decreased production, increased labor and medication costs, decreased ewe longevity and higher culling rates. Foot rot can be a wicked health problem in sheep or can be a mild annoyance.
The only good thing I can think of about foot rot is that it can give the dogs a lot of chute work through the footbath and some gathering and shedding work.
Prevention of foot rot is the only practical way of dealing with this problem. Avoid foot rot like the plague.
Causes of Foot Rot
Foot rot is caused by a synergistic action of two anaerobic bacteria, along with environmental conditions conducive to their growth and spread. The bacteria are: Fusobacterium Necrophorum and Bacterioides Nodusus.
The bacteria F. Necrophorum is commonly present in soil, manure, etc. It is the B. Nodusus organism, when present, that causes the problem. Again, both bacteria have to be present to cause foot rot. There are over 20 strains of the B Nodusus bacteria, varying in their infectivity and severity.
Warmth, mud and poor sanitation are environmental conditions that also favor foot rot spread. These conditions create the anaerobic (lack of oxygen) conditions necessary for the spread of the disease. The B. Nodusus organism will only live in soil for 14 to 21 days.
Preventing Foot Rot
At the risk of being annoying, I want to repeat the statement, avoid foot rot at all costs. If nothing but this point is remembered, this article will have been successful.
There are mountains of misinformation that are spread about foot rot. Remember this also: foot rot is spread by sheep carrying the disease. Certainly, foot rot can be spread through equipment and contaminated premises. However, the overwhelming cause of foot rot in clean flocks is through introduction of sheep carrying the disease. Most people that get foot rot in their flock, buy it. Not a good bargain.
Foot rot bacteria can live in cracks and crevices of a sheep’s hoof for months. Often, they will not even limp until environmental conditions are right to activate a case of foot rot.
Buy sheep from a flock that is free of foot rot. Isolate all new purchases for at least 30 days. Buy sheep from honest breeders that will honestly tell you their health problems. Be incredibly cautious about buying “bargain” sheep at the sale barn, etc. A free sheep with foot rot will be an incredibly expensive individual.
Treating Foot Rot
For those fighting foot rot, the goal is to dry out the infected feet and introduce oxygen. This is accomplished by using chemical drying agents and close trimming of infected feet.
Some of the chemicals used are: zinc sulfate, copper sulfate, and formaldehyde. These chemicals are usually used in a footbath or soaking area. Zinc sulfate is usually the best, safest compound for man and beast. Antibiotics can also be used to help cure foot rot. When available, the foot rot vaccine can also be helpful in the foot rot fight.
Keeping feet trimmed of overgrown tissue will reduce mud and manure packing, and decrease the chances an anaerobic environment will develop. Sheep that have foot rot should be trimmed ruthlessly. Do not be frightened of a bit of blood.
It is important to separate infected sheep into their own hospital group and away from those not infected. This allows you to concentrate your efforts on the infected sheep and helps prevent further spread of the disease. Since foot rot lives in soil for only two to three weeks, used planned pasture rotating to your advantage.
Some breeds, lines or individual sheep seem to have a propensity for susceptibility to foot rot. If you have some sheep that cannot be cured, culling may be the best strategy. If you have a small flock of grade sheep, it may be more feasible to sell the whole flock and buy more sheep in two to three weeks.
Do not believe the old wives’ tales about foot rot. Foot rot is most commonly spread by infected sheep entering an uninfected flock. Do not buy foot rot! Prevention is the best cure.