Prevalence of mastitis and isolation of Escherichia coli from mastitic cows in Maya City, Eastern Hararghe Zone, Oromia, Ethiopia

Abstract Mastitis is the most economically significant disease affecting lactating dairy cows worldwide. From November 2023 to April 2024, a cross-sectional study was carried out in Maya City, eastern Hararghe zone, to assess the prevalence of mastitis in lactating dairy cows, identify related risk factors, and examine the antibiogram profiles of Escherichia coli from raw cow milk. Mastitic animals were detected by physical examination of udders and the California Mastitis Test. Then, bacterial culture and biochemical tests were employed to isolate E. coli. And antibiogram pattern of E. coli was assessed by the disk diffusion method. A simple random sampling was used to choose 353 lactating dairy cows. Of the 353 dairy cows examined for bovine mastitis, 137 were positive, with an overall prevalence of 38.8% (95% CI 33.8–44.1). Out of these, 7.1% (95% CI 4.8–10.3) and 31.7% (95% CI 27.1–36.8) had clinical and subclinical mastitis, respectively. Mastitis had a quarter-level prevalence of 19.4% (95% CI 15.6–23.9), with clinical cases accounting for 4.3% and subclinical for 15.1%. Furthermore, 3.6% (95% CI 1.9–5.6) of the teats were blind. There was a significant association (p < 0.05) between the prevalence of mastitis in lactating dairy cows and risk factors: lactation stage, body condition score, previous mastitis history, teat lesion, farm size, milking mastitic cow at the end, and cow hygiene. Accordingly, cows with teat lesions were four times more likely to have mastitis than cows without teat lesions (OR 4.27; 95% CI 1.36–13.35). Of the 274 milk samples tested, 22.6% were positive for E. coli . All 62 E. coli isolates were 100% sensitive to ciprofloxacin and chloramphenicol. This study revealed that bovine mastitis was moderately prevalent in the study area. Thus, mastitis control measures should be developed with a focus on subclinical mastitis while considering the related risk factors.