ISOLATION OF SELECTED BACTERIAL PATHOGENS FROM BOVINE MASTITIS IN SELECTED DAIRY FARMS FOUND IN DIRE DAWA TOWN, EASTERN ETHIOPIA

Abstract

Mastitis in cattle is a complex and multi-factorial disease caused by an interaction between three major factors: the animal, pathogens, and the environment. A cross-sectional study was conducted from June 2022 to November 2022 to estimate the prevalence of mastitis in lactating cows, to assess the risk factors for bovine mastitis, and to isolate and identify coliform and gram-positive cocci bacteria involved in the mastitis cases from dairy farms in Dire Dawa, Eastern Ethiopia. Detection of mastitic animal was done based on physical examination of udders and CMT test. Bacterial culture and biochemical tests were employed to identify the target pathogens. A total of 366 dairy cows and 1,464 quarters were screened for mastitis. Overall prevalence of mastitis at cow and quarter levels were 24.04 and 13.5%%, respectively. Age, parity, cows udder position, history of mastitis, barn floor, milking sequences of clinically mastitic cows and leg and udder hygiene scores were found to be risk factors significantly (P<0.05) associated with mastitis. From the 191 mastitis-positive milk samples 82.7% (158/191) were culture positive. Out of the isolates from clinical cases (n=59) and isolates from sub clinical cases (n=99), Staphylococcus aureus (22%) and E. coli (15.7%) were predominant isolate. The other bacterial isolate in order of abundance, Coagulase Negative Staphylococcus (10.5%), Streptococcus agalactiae (6.8), Streptococcus dysgalactiae (5.8%), Staphylococcus intermedius (4.7%), Staphylococcus hyicus (4.2%), Klebsiella pneumoniae (3.1%), Micrococci spp (2%), Streptococcus uberis (1.6%), Enterobacter aerogenes (1%), and Enterococci spp (0.5%). The study showed that high parity number (OR = 19.5; p = 0.005), moderate parity (OR = 10.9; p = 0.022) and history of mastitis in preceding lactation (OR = 28.4; p = 0.001) were the major risk factors which are significantly associated with higher prevalence of S. aureus. History of mastitis in preceding lactation (OR = 3.7; p = 0.021) and very dirty (OR = 3.9; p = 0.005) udder and legs were the major risk factors which are significantly associated with higher prevalence of E. coli. Therefore, hygienic milking practice, adequate sanitation of the dairy environment, proper attention to the health of mammary glands and regular screening tests should get emphases as control strategies