Prevalence and Risk Factors of Clinical Mastitis in Holstein Cows under Subtropical Egyptian Conditions

Abstract

The current study was built on 1015 dairy records of Holstein Friesian cows, aimed to determine the prevalence and risk factors of clinical mastitis (CM). Logistic regression models were conducted to determine the risk factors associated with the onset of CM. The average age at 1st calving was 1.98 years in mastitic cows, and 2.01 years in healthy onest. DMY was shown to be somewhat lower in mastitic cows than in healthy (31.9 and 32.3 kg, respectively). Older dairy cows >5 years had a higher incidence of mastitis (53.56%). The prevalence of CM was higher in multiparous cows, either 2nd parity (48.24%) or ≥ 3rd parity (47.23%). Regarding the calving season, cows that calved in winter showed a lower percentage of CM (38.36%). Pregnant cows were found to have a greater incidence of CM than non-pregnant cows (59.35% and 32.89%, respectively). Concerning the history of the previous mastitis, cows that were infected previously showed a higher prevalence of CM (51.66%). The greatest percentage of CM was observed in cows in the early and mid stages of lactation (44.59% and 52.69%, respectively). The final multivariate logistic regression model revealed that age at 1st calving had a significant positive correlation with the incidence of CM (β=1.19, P-value= 0.003). Older cows >5 years ( (OR=1.79), cows calved during the summer season (OR=1.84), Pregnant cows (OR=7.27), cows with a history of previous mastitis (OR=1.81), and lactating cows at early lactation stage (1-90 days) were significant risk factors associated with an increased incidence of CM.