Predisposing factors and control of bacterial mastitis in dairy ewes

Abstract

Bacterial mastitis is a major health problem in dairy sheep worldwide. It is associated with reduced milk yield and occasionally involuntary culling of affected ewes, as well as insufficient growth and mortality of lambs. In general, the incidence of clinical mastitis in ewes during lactation is lower than 5%. However, the prevalence of subclinical mastitis is variable ranging from 10-30% or more. In clinical cases of bacterial intramammary infections, Staphylococcus aureus is dominant. In the case of subclinical mastitis the prevailing isolates are Coagulase-Negative Staphylococci(CNS). Moreover, predisposing factors related to the environment, genetics, udder morphology and nutrition, are likely to contribute to the occurrence of mastitis. Hence, control of the latter factors and bacteriological contamination during milking are the main preventive measures. The notion is that detection of the ovine genome regions involved in mastitis resistance will also facilitate the most effective control of mastitis in flock level. Appropriate genetic selection, together with the implementation of preventive measures, could reduce the negative consequences of bacterial mastitis.