Temporal and farm-management-associated variation in the faecal-pat prevalence of Campylobacter jejuni in ruminants.

In a 2-year longitudinal study of adult animals on 15 dairy farms and four sheep farms in Lancashire, UK. C. jejuni was isolated from all farms, although not on every occasion. Faecal samples were collected and cultured using standard techniques for isolation of Campylobacter. Assignment to species was via PCR assays. Peak prevalence of C. jejuni in both cattle and sheep was observed during the summer and in cattle this apparent seasonality was associated with grazing pasture [odds ratio (OR) 2.14], while in sheep it was independent of grazing. Increased prevalence was associated with increased milk yield (OR 1.05) and herd size (OR 1.01) in dairy cattle, and with increased stocking density (OR 1.29) and pasture quality (OR 2.16) in sheep. There was considerable variation in prevalence between farms but no evidence of large-scale spatial variation. The association between C. jejuni prevalence and diet in dairy cattle deserves further investigation.