CASE-CONTROL STUDY OF RISK-FACTORS FOR TOXIC MASTITIS IN 26 DAIRY HERDS

A retrospective case control study of farm level risk factors for toxi c mastitis was carried out in November and December 1996. Twenty-six f arms from mid-Somerset were visited: 13 case farms (had had a cow with toxic mastitis in the previous year) and 13 geographically matched co ntrols (no case of toxic mastitis). The farmers were interviewed and t he buildings were examined. Information was collected on the type and quality of housing, usual milking routines, milk quality and mastitis prevalence in the previous year. All the data were collected on to pre tested recording sheets and loaded into a database. Simple and complex analysis was done. The following variable were significantly (P < 0.0 5) associated with an increased risk of toxic mastitis in the simple a nalysis: housing cows in October rather than November; a low number of calving boxes per cow; a high proportion of cows with intermediate bo dy condition and low herd bulk milk somatic cell counts (HBMSCC). In t he final model low HBMSCC and a high proportion of cows with intermedi ate body condition remained significant. The authors conclude that, de spite the small size sample, the results of this study are consistent, plausible and support the information from previous experimental and observational studies about the role of somatic cell counts in toxic m astitis.