Survey of the incidence and aetiology of mastitis on dairy farms in England and Wales

TLDR

A random sample of 97 dairy farms in England and Wales was surveyed, with farmers collecting aseptic milk from five consecutive clinical mastitis cases and five high‑somatic‑cell‑count quarters using a defined protocol and completing a questionnaire, and samples were gathered throughout the year. Incidence of clinical mastitis averaged 47 cases per 100 cows per year from farm records and 71 per 100 cows per year from sampled cases, with Streptococcus uberis and Escherichia coli isolated in 23.5 % and 19.8 % of clinical samples respectively and 26.5 % yielding no growth, while high somatic cell count samples most frequently contained coagulase‑negative staphylococci (15 %), S.

Abstract

A survey of clinical and subclinical mastitis was carried out on 97 dairy farms in England and Wales, selected at random from members of a national milk recording scheme. The farmers were asked to collect aseptic milk samples from five consecutive cases of clinical mastitis and from five quarters with high somatic cell counts using a defined protocol, and they completed a questionnaire that included information on the cows sampled, the herd and the history of mastitis in the herd. The samples were collected throughout the year. The mean incidence of clinical mastitis was 47 cases per 100 cows per year (estimated from historic farm records) and 71 cases per 100 cows per year (estimated from the samples collected). Streptococcus uberis and Escherichia coli were isolated in pure culture from 23·5 per cent and 19·8 per cent, respectively, of the clinical samples; 26·5 per cent of the clinical samples produced no growth. The most common isolates from the samples with high cell counts were coagulase‐negative staphylococci (15 per cent), S uberis (14 per cent) and Corynebacterium species (10 per cent). Staphylococcus aureus and coagulase‐positive staphylococci together accounted for 10 per cent of the samples with high somatic cell counts; 39 per cent produced no bacterial growth.