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Anna Campbell

Fellow – Anna Campbell

Mentor – Kevin Washburn

Project – The response of selected sheep and goat populations to the treatment of caseous lymphadenitis with tulathromycin

Objective – To investigate the effectiveness of treating sheep and goats with naturally-occurring caseous lymphadenitis with tulathromycin at decreasing clinical prevalence and increasing the rate of resolution.

Sample Population – 827-919 sheep and goats in west Texas.

Procedure – Each animal was inspected in February and June, 2009 for lymph node abscesses consistent with CL. Serum was also collected from each animal and tested for CL antibodies. Animals with CL-like lesions were separated and randomly placed into either a treatment group, receiving tulathromycin, or a control group, receiving saline. CL was confirmed by culturing abscess aspirates. Cases were re-examined one month after treatment and classified as resolved or unresolved.

Results – According to data from the February trip, there was a significant difference in percents of resolution between the treatment (66.6% resolved) and control (44.8% resolved) groups (P < 0.0027). There was also an overall decrease in clinical prevalence between the first and second time periods (6.96% and 3.51% respectively). Additionally, while the data showed a greater serological prevalence than clinical prevalence on trip one, only 54.8% of the 31 culture positive animals were serologically positive.

Conclusion and Clinical Relevance – In most instances, the data suggested that treatment with tulathromycin aided in the resolution of clinical CL, may have helped decrease the number of clinical cases, and appeared to decrease the clinical prevalence of CL. These treatment methods may be acceptable for treating CL without opening abscesses. Finally, serological testing of animals may not be appropriate for detecting clinical CL.