Coliform organisms associated with milk of cows with mastitis and their sensitivity to commonly available antibiotics in Kaduna State, Nigeria

An examination of raw milk for the isolation of coliforms as members of mastitis-causing organisms was conducted on 300 cows from four Local Government Areas in Kaduna State, northern Nigeria. A 10.3% prevalence was recorded for coliform organisms using the Microgen GN-ID A+B Kit (Medica-TecTM), these were; Enterobacter spp., Citrobacter spp., Klebsiella spp., Serratia marcescens, Proteus spp. and Pantoea agglomerans (similar to Enterobacter aerogenes). Antibiotic sensitivity test using commonly available antibiotics showed that all isolates were sensitive to amoxicillin and ciprofloxacin, but resistant to tetracycline and erythromycin. Age, parity number, stage of lactation, management system, hygiene of milking process, and presence of lesion on udder/teat were found to be significantly associated (p<0.05) with the prevalence of mastitis in cows. The lowest prevalence (24%; 48 of 200) was recorded in cows within 3 to 4 years of age while, the highest (60.6%; 20 of 33) was in cows aged above 5 years. Stage of lactation was significant with the prevalence of mastitis being the highest (45.5%; 30 of 66) during the initial stage of lactation (0 to 5 month). It was concluded that, the relatively high prevalence of coliforms in bovine mastitis in dairy herds could significantly reduce milk production and cause economic losses. Good hygiene in milking process, milking clinically infected cows last, culling chronic mastitis cases, treating clinically infected cows and dry period therapy could reduce the prevalence of coliform mastitis in Kaduna State, Nigeria. Key words: Cow, milk, mastitis, coliforms, antibiotic sensitivity.