Fecal excretion of <em>Campylobacter jejuni</em> by young dairy calves and the relationship with neonatal immunity and personality traits

<p><strong>Aims</strong>: 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 <em>Campylobacter jejuni</em>, neonatal immunity, and personality traits of calves.</p> <p><strong>Methods and results</strong>: 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 <em>C. jejuni</em> 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 <em>C. jejuni</em>.</p> <p><strong>Conclusions</strong>: Overall, the findings indicate that the immunity of neonatal dairy animals and possibly the animal’s behavior may contribute to the fecal shedding of <em>C. jejuni</em>.</p>