Difficulties with hooves (Shepherd’s Notebook)
(Editor’s note: Susan Schoenian is a retired sheep and goat specialist for the University of Maryland.)
Footrot is one of the worst and unfortunately most common diseases affecting small ruminants, especially sheep. In fact, it is often cited as one of the main reasons for exiting the industry.
Its “cousin,” foot scald, can also be a serious concern for sheep and goat producers.
Foot scald (also called interdigital dermatitis) is an infection (or inflammation) in the skin between the digits of the hoof.
It is usually caused by a soil-borne bacteria (Fusobacterium necrophorum). This bacterium can live in the soil for an extended period of time. It is the precursor or facilitator to footrot.
Footrot is an infection of the tissue of the hoof.
It can be benign (mild) or virulent (more invasive), depending upon the strain.
Footrot requires a second bacteria (Dichelobacter nodosus) to cause disease.
D. nodosus is usually introduced to the farm via infected animals, less commonly by contaminated vehicles or footwear.
Unlike scald, footrot is highly contagious. However, the bacteria that causes footrot has a more limited lifespan outside the animal: only two weeks.
This two-week period is key to disease eradication.
Traditional treatment options for footrot/scald usually involve hoof trimming, repetitive foot bathing (in solutions of zinc sulfate), separation of infected and healthy animals, movement of animals to clean, dry areas and culling.
Culling is probably the most powerful tool for dealing with footrot.
Animals which get re-infected or fail to respond to treatment(s) should be culled.
In more recent years, antibiotics have been advocated for the treatment of footrot.
Zactran (gamithromycin), a long-acting prescription antibiotic, has been proven (in research trials) to be highly effective against footrot (in sheep).
However, it is an expensive option. Penicillin and oxytetracycline (e.g., LA-200) are less expensive options (extra label).
How hoof disease is treated is often dependent on the number of animals on the farm and the equipment available for handling.
Some producers routinely foot bathe their animals or have them regularly walk through a foot bath. A box with dry chemicals can also be used to reduce the spread of hoof disease.
For lesser animals, there are various topical treatments that can be applied to individual hooves.
A more concentrated solution of zinc sulfate can be sprayed directly on the hooves.
In fact, this is a good idea after hoof trimming, along with disinfecting hoof shears between animals.
There are various over-the-counter preparations (sprays and pastes) that can be used to treat individual cases.
There are vaccines for footrot, but none are currently available.
The California Wool Growers Association has been able to import a footrot vaccine (Footvax) from New Zealand, but so far, its efforts have not expanded beyond a few western states.
The footrot vaccine is not used to prevent foot rot, but rather to reduce the incidence on farms where the disease is already present.
It goes without saying that hooves should not be ignored.
While overzealous hoof trimming is discouraged, routine hoof care is an important component of flock/herd health.
Lameness (due to hoof disease) is both an animal health and welfare issue.
Lame animals experience pain and discomfort. They eat less and have reduced levels of productivity.