Risk factors associated with repeated cases of clinical mastitis in high producing dairy cows

Abstract

Due to the control and eradication of contagious pathogens in herds that produce high quality milk, environmental clinical mastitis (CM) has become one of the main emerging problems. Clinical mastitis results in financial losses and its treatment is the main cause of milk contamination with antibiotic residues. Little is known about the risk factors that determine the occurrence of repeated cases of CM in the same lactation. These cases result in frustration relative to treatments (fail to recover) and great economic losses (need for extended and repeated therapy). In this context, a case-control study will be conducted to identify risk factors for the occurrence of repeated CM cases e estimate the probability of subsequent cases for cows that experienced one or two cases in the same lactation. High- producing cows from a dairy herd will be observed for eight months, during which microbiological cultures of milk and epidemiologic information will be obtained from all animals that develop incident cases of CM. For each case, the same information will be obtained from three control cows randomly selected within the same stage of lactation. Logistic regression will be used to identify risk factors for a repeated case of CM such as physical characteristics of teats and udders, milk production, and parity. Results of this study will aid dairy producers to improve milk quality, animal well-being, and the safety of dairy products offered to the population. (AU)