Factors Contributing to Differential Risk Between Heifers in Contracting Summer Mastitis

Abstract

A survey is given of factors which may contribute to differential risk between heifers in contracting summer mastitis. These include such aspects as genetic background and the physiological condition of the individual. As yet very little attention has been paid to the causal factors which lead to increased risk. One aspect that has been largely ignored is the cause underlying relative differences in attractiveness to flies, particularly Hydrotaea irritans and the accompanying increase in probability of transmission. Data are given which indicate that odour signals emanating from the individual contribute to differential risk.