Texas AgriLife Research
2147 TAMU,
The
Prevalence of Caeous Lymphadenitis in Selected Goat Populations and the Impact
of Treatment with
Tulathromycin Versus CUlling Affected Animals
According to a large 2002 survey, the population of goats in the United States has risen substantially over the past few years, and, more currently, this trend has continued. Caseous lymphadenitis (CL), caused by the bacteria Mycobacterium pseudotuberculosis, is an important disease for the goat and sheep industry. One study of culled sheep from the Western United States found that this disease was the third leading cause of economic loss, and another report found the prevalence of CL in sheep from 9 Western states to be 42%. Unfortunately, to date, such prevalence studies of CL in large goat populations are lacking. One difficulty in establishing prevalence within populations is the detection of sub-clinical disease. A commonly utilized blood test only looks for antibody levels to CL, but does not consistently define disease status (whether they have real lesions, or have just been exposed). Treatment of this disease varies from culling affected animals from the herd, opening, flushing and draining characteristic abscesses associated with the disease to the use of formalin (a known carcinogen) injected directly into the lesion. Over the past 18 months, our "team" has investigated a new therapy for this disease involving the use of an antibiotic (tulathromycin) injected both in the lesion and under the skin in the neck. This therapy has proven to be comparatively effective and safe and poses less risk of spreading the disease than the standard therapy. The goals of our project with this grant would include the following: test three populations of goats for the presence of antibodies to CL, identify goats with abscesses and culture them to confirm the presence or absence of CL (find the true prevalence), treat goats with these characteristic signs of CL with tulathromycin in one of the three herds and evaluate how treatment affects prevalence compared to culling affected animals in other herds.