Staphylococcus aureus in mastitic crossbreed cows and its associated risk factors in Addis Ababa City, Ethiopia

Abstract

A cross sectional study was conducted in dairy farms of Addis Ababa city from November 2011 to April 2012 to estimate the prevalence of Staphylococcus aureus and its associated risk factors in mastitic dairy cows. Milk samples were collected from 153 (50 clinical and 103 subclinical) mastitic lactating crossbred cows and were subjected to laboratory examination for identification of Staphylococcus aureus. Of the 153 mastitic cows, 67 were Zebu-Holstein Frisian and 86 were ZebuJersey crossbred. Bacterial identification was based on colony morphology, gram staining characteristics, and enzymatic tests including catalase and coagulase. Staphylococcus aureus was identified in 74 (48.4%) milk samples. It was higher (n= 63, 61.1 %) in subclinical cases as compared to clinical form of the disease (n= 11, 22%). The occurrence of bovine mastitis associated with Staphylococcus aureus varied significantly (p<0.05) between breed, lactation stage, parity and age. It was higher (n= 49, 56.9%) in Zebu-Jersey than Zebu-Holstein Frisian (n= 25, 37.3%) crossbred cows. Staphyloccocal mastitis is a major health problem in dairy farm of Addis Ababa causing huge economic loss. Furthermore, Staphylococcus aureus can leads to public health hazard through consumption of raw milk or milk products from infected animals. Therefore, early diagnosis and screening of cows for mastitis is important to limit spread of the disease. Appropriate control and prevention measures should be in place to reduce Staphylococcus aureus mediated bovine mastitis. Routine pasteurization of milk should also be practiced to safeguard the public health.

Keywords: Addis Ababa, Crossbred Cows, Prevalence, Mastitis, Staphylococcus aureus