Study on Bovine Mastitis: Prevalence, Bacteriological Examination and Assessment of Milk Loss in Durame Town and Its Surrounding District, Southern Ethiopia

Abstract

Mastitis is a multifaceted dairy cattle disease with multiple causative agents and economic loss. Cross-sectional study on bovine mastitis prevalence and subclinical mastitis milk yield loss in Durame town and its surrounding district was conducted from January to September 2019 to estimate the prevalence, milk yield losses, associated risk factors and antimicrobial susceptibility testing of the isolates. Californian Mastitis Test, bacteriological culturing, antimicrobial susceptibility test and split-udder trial was conducted to determine production losses. Out of 384 lactating dairy cows were selected from the sampling frame list picked randomly by the simple random sampling method, a total 220 (57.3%) cows were found positive for mastitis: 2.1% clinical and 55.2% sub-clinical. The prevalence in Durame and its surrounding were 78.2% and 53.8%, respectively. Among assessed risk factors, mastitis was 2.5 times higher in the crossbred than local. Prevalence was 2.6 times higher in cows having 6 or more compared to cows having 1–3 calving, Cows in the early lactation were more likely to have mastitis than cows in the late lactation stage. Cows in herds without bedding material were more likely to have mastitis than those cows in farms with bedding material. Cows in farms that did not milk mastitic cows last were more likely to have mastitis than those cows in herds that practice milking mastitic cow at last. Herds feeding their cows before milking were 5.128 times more likely to have mastitis than herds feeding their cows after milking, house floor with non-concrete and barn cleaning once were more likely associated with the udder infection. The most common bacterial isolates were Coagulase-negative Staphylococci (35.5%), Staphylococcus aureus (30.5%), Streptococcus agalactia (15%), E. coli (11.6%), Staphylococcus intermidus (1.8%) and streptococcus uberis (4.3%). The majority of isolates were highly sensitive to Gentamycin (98.3%) and resistant to Polymixyn. The mean milk yield for uninfected healthy quarters was 0.995kg per milking and the rates of milk reduction in infected quarters were 6.2%, 24%, and 50.5%. Quarters with Californian Mastitis Test trace and 1 were combined and considered negligible. Subclinical mastitis lost an average of 22% of its milk production and causes an estimated total loss for each cow per lactation was 2884.59 Eth Birr. Reducing risk factors, early diagnosis and regular screening of cows together with the proper therapeutic management are important to reduce mastitis