Use of a staphylococcal vaccine to reduce prevalence of mastitis and lower somatic cell counts in a registered Saanen dairy goat herd
Kautz, Felicia M.
Nickerson, Stephen C.
Ely, Lane O.
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The purpose of this investigation was to evaluate the efficacy of a staphylococcal bacterin (Lysigin®) in reducing the prevalence of staphylococcal mastitis and somatic cell counts (SCC) in a commercial dairy goat herd. Does were vaccinated (n = 15) or left as controls (n = 15) and the levels of mastitis and SCC were monitored at approximately 6-wk intervals over an 18-mo period. Prior to and after vaccination, Staphylococcus caprae (42.5%), S. xylosus (15.1%), and S. simulans (10.0%) were the predominant causes of intramammary infections (IMI) in the herd. The new infection rate was 1.64 IMI/doe among vaccinates, which was lower than but not different (P < 0.12) from controls (2.67 IMI/doe). The majority of new IMI across treatments were caused by S. caprae (31.7%) and S. xylosus (23.9%). The spontaneous cure rate of existing IMI after immunization was 1.28 cures/doe in vaccinates, which was higher than that observed in controls (0.6 cures/doe; P < 0.043); the majority of spontaneous cures occurred with S. caprae (44.4%) and S. xylosus (22.3%). Average SCC from milk samples of vaccinated does over the trial showed a tendency to be lower than that of nonvaccinated controls (1274 x 10³/ml vs. 1529 x 10³/ml, respectively) (P < 0.10). In addition, bulk tank SCC averaged for the 5 pre-vaccination sampling dates was 1293 x 10³/ml, and for the 14 post-vaccination dates, SCC averaged 1052 x 10³/ml. The freezing of milk samples had no deleterious effect on determining SCC. Results support the continued study of mastitis vaccines for use in managing staphylococcal mastitis and SCC in dairy goats. Key words: Dairy goat, Mastitis, Somatic cell count, Vaccination