ABSTRACT
Mastitis is a multi-etiological and complex disease causing inflammation of parenchyma of mammary glands is a problem in many dairy herds. The objective of this study was isolation and identification of the pathogenic bacteria that cause bovine clinical mastitis. A cross sectional study was undertaken from November 2018 to April 2019 on small scale and government dairy farms in Asella town. Cows were examined directly at quarter and teat level for clinical manifestation. A total of 83 milk samples were collected from 46 cows that shows clinical sign of mastitis from a total of 12 farms. Isolation and identification of major bacterial species was carried out by culturing on different media and using primary and secondary biochemical tests. Out of the 83 samples collected and examined, all (100%) were positive for cultural isolation of bacterial species. The bacteria were identified to genus and species level. Among the 83 isolates 32 (38.6%) were S. aureus, 24 (28.9%) were Staphylococcus intermedius and 6 (7.2%) were Staphyloco ccus hyicus, other bacteria like Escherichia coli 12(14.5%), Streptococcus species 2 (2.4%) were also isolated. Bacillus Species 2 (2.4%), Proteus species 2(2.4%) and 3 (3.6%) of them were mixed bacterial infections. The present study revealed that both contagious and environmental bacterial pathogens were responsible for the occurrence of clinical mastitis. Proper milking practices and farm husbandry practices as well as future detailed studies up to the species level and on antibiotic profiles of the pathogens are needed.
