Journal Articles

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    Population dynamics of Campylobacter jejuni in healthy dairy calves reared with and without exposure to wild birds
    (Oxford University Press on behalf of Applied Microbiology International, 2025-12-01) Rapp D; Ross CM; Tegetmeyer HE; Maclean P; French NP; Brightwell G
    Introduction In order to understand the emergence, persistence, and transmission of Campylobacter jejuni in livestock, this longitudinal study characterized the C. jejuni population in young calves and assessed the impact of exposure to wild birds during the pre-weaning period. Methods and results Faecal samples were collected on eight occasions from 48 calves housed in three pens between birth and 10 weeks of age, two of the pens being covered with orchard netting. From the 250 C. jejuni isolates obtained from the positive faeces, seven distinct sequence types (7-gene legacy MLST) were identified, with high genetic similarity of circulating strains. On each pen, sequential dominance of ST was observed, with ST-508 and ST-50 prevalent in calves under 4 weeks old, and ST-520 or ST-422 prevalent in the 8- to 10-week-old calves. Exposure of calves to wild birds did not influence genotypes distribution, α-diversity, and community dissimilarity. However, a difference in C. jejuni populations between the two groups of calves that were not exposed to birds suggests that calving rank may shape the type and succession of ST detected over time. Conclusion This study provided no evidence for exposure to wild birds being a driver for C. jejuni population changes in healthy pre-weaned calves.
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    Fecal excretion of Campylobacter jejuni by young dairy calves and the relationship with neonatal immunity and personality traits
    (Oxford University Press on behalf of Applied Microbiology International, 2023-04-29) Rapp D; Schütz KE; Ross C; Sutherland MA; Hempstead MN; Hannaford R; Cave VM; Brightwell G
    Aims Zoonotic pathogens in bovine herds are major concerns for human and animal health, but their monitoring in animals can be challenging in the absence of clinical signs. Our objective was to determine the association between fecal excretion of Campylobacter jejuni, neonatal immunity, and personality traits of calves. Methods and results Forty-eight dairy calves were reared in three indoor pens from birth to 4 weeks of life. Microbial analyses of the fecal samples collected weekly revealed that the proportion of calves naturally contaminated with C. jejuni in each pen reached 70% after 3 weeks of life. High (>16 g l−1) levels of IgG levels in the serum of neonatal calves were negatively (P = .04) associated with fecal detection of C. jejuni over the trial period. Calves that spent more time interacting with a novel object tended to be positive (P = .058) for C. jejuni. Conclusions Overall, the findings indicate that the immunity of neonatal dairy animals and possibly the animal’s behavior may contribute to the fecal shedding of C. jejuni.