Prevalence, bacterial etiology and risk factors of subclinical mastitis in dairy goats in Nyeri County of Kenya

Abstract

A cross-sectional survey was conducted in April 2014 in Nyeri County to determine the prevalence of subclinical mastitis, its risk factors and bacterial causes with their antibiotic sensitivities in dairy goats. California Mastitis Test (CMT) was performed on 61 randomly selected lactating goats while risk factors and farmers’ knowledge, awareness, perceptions and practices (KAPP) were determined via observation during farm visits and administration of 25 questionnaires. Bacterial causes of mastitis were determined through culture of milk samples and bacteriological identification. In vitro antibiotic sensitivity was evaluated for 14 Staphylococci and 4 Streptococci by subjecting them to 8 common antibiotics using disc diffusion method. Prevalence of subclinical mastitis at goat level was (33%) which was significantly associated with grazing system, stage of lactation and milk yield (P<0.05). The most isolated bacterium was Staphylococci (34%), followed by Streptococci (6%). Staphylococci had 100% sensitivity to gentamycicn, kanamycin, streptomycin and chloramphenicol antibiotics, but demonstrated resistance against sulphamethoxazole and co-Trimoxazole. Streptococci were sensitive to eight antibiotics with only slight resistance against sulphamethoxazole. The high prevalence of subclinical mastitis revealed in Nyeri calls for concerted control measures. The high isolation rate of Staphylococcus species signals the need for improvement of the hygienic standards of these goats during milking and within their pens. Very low antibiotic resistance in the area indicates that most commonly used antibiotics for mastitis are effective.

Keywords: Dairy goats, subclinical mastitis, prevalence, etiology, Kenya