Mastitis in dairy cows: Prevalence, risk factors and Antimicrobial Susceptibility Test of major Bacterial isolates in Adea Berga District

Abstract

A cross-sectional study was executed from September 2022 to June 2022 in the Adea Berga district to estimate the prevalence of mastitis, identify potential risk factors, and isolate udder pathogens with subsequent antimicrobial susceptibility testing. A total of 326 lactating cows (1254 quarters) were examined by physical examination of the udder and California Mastitis Tests. Risk factors supposed to be associated with mastitis were assessed and recorded in the data collection format and analyzed using Chi-square and Logistic regression models. The result indicated that the overall prevalence of mastitis at the cow level was 45.7% (95% CI:0.404–0.511). The risk factors analysis indicated Breed (ꭓ2 =6.55; P = 0.01), Age Category (ꭓ2 =46.47; P = 0.00), Lactation phase (ꭓ2 =41.96; P = 0.07), Parity (ꭓ2 =47.32; P = 0.00), and Hygiene (ꭓ2 =26.99; P = 0.00) of the cows showed statistically significant association with mastitis based on Chi-Square Analysis. Other factors like study kebeles, daily milk yield of each cow, and the existence of the affected quarter were also evaluated and did not show a statistically significant association with mastitis occurrence(P > 0.05). Based on Multiple Logistic regression analysis, old cows were 3.17 times more affected by mastitis (OR = 3.17, 95%CI = 0.051,2.267; P = 0.04) when compared with the young adult age group. Cows at the late-lactation stage are 5.38 times more reactor for mastitis than those at the early lactation stage (OR = 5.38, 95%CI = 1.014, 2.383, P = 0.00). Multiparous and cows with poor hygiene are 3.5 and 2.87 times more affected by mastitis when compared with Uniparous and cows with good hygiene respectively. The most common pathogens isolated were Staphylococcus aureus (45.16%), followed by Staphylococcus epidermidis (29%). All isolated bacterial pathogens were tested against different antimicrobial discs to evaluate the level of their susceptibility. Accordingly, the majority of the pathogens showed greatest resistance to penicillin, whereas most of them were found susceptible to tetracycline and gentamicin, respectively. The results of the present study indicated that mastitis is a common health problem of dairy animals with significant economic impact and public health importance. Hence improving dairy herds management and implementation of the one health concept is important to combat the economic and public health impact of this disease.