Factors involved in the epidemiology and control of Streptococcus uberis and coliform mastitis

Abstract

Streptococcus uberis and coliforms were the major pathogens most frequently isolated from clinical mastitis cases in a within-herd comparison of full treatment (teat dipping and dry-cow therapy) with partial treatment (only selective dry-cow therapy) carried out in five commercial dairy herds for a two-year period. Differences in the epidemiology of these types of mastitis were shown. a) The rate of Str. uberis mastitis was 72% higher in the partial control group than in the full control group, while the rate of coliform mastitis was 18% lower in the partial control group. b) Forty per cent of Str. uberis but only 14% of coliform clinical mastitis cases occurred during the dry period or within 48 h of calving. Thirty-eight per cent of Str. uberis but only 6% of coliform clinical mastitis cases found during lactation occurred in quarters subclinically infected with the same pathogen at calving. c) There was an apparent association between poorer winter housing and higher rates of new coliform infections but this did not apply to new Str. uberis infections. Str. uberis was isolated in large numbers from 13% of teat ends of dry cows in three of the herds during one summer and was the major pathogen most frequently isolated from cases of dry-cow mastitis.