Accuracy of clinicians in predicting the bacterial cause of clinical bovine mastitis.

We examined the ability of clinicians to predict the causative organism of bovine mastitis in our practice. We obtained 118 milk culture results from 112 mastitic cows and compared the culture results to the predictions of clinicians at the time of milk sample collection. Sixty of 118 culture results were accurately predicted. The positive predictive value for coliform mastitis was 42% and the negative predictive value was 79% in a study population with a 31% prevalence of coliform mastitis. The proportion of coliform positive cultures accurately predicted was significantly greater than that expected by chance (p < 0.02).