Rapp DSchütz KERoss CSutherland MAHempstead MNHannaford RCave VMBrightwell G2025-12-042023-04-29Rapp D, Schütz KE, Ross C, Sutherland MA, Hempstead MN, Hannaford R, Cave VM, Brightwell G. (2023). Fecal excretion of Campylobacter jejuni by young dairy calves and the relationship with neonatal immunity and personality traits. Journal of Applied Microbiology. 134. 5.1364-5072https://mro.massey.ac.nz/handle/10179/73912Aims 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.CC BY-NC 4.0(c) 2023 The Author/shttps://creativecommons.org/licenses/by-nc/4.0/zoonosisCampylobacter jejunidairy calvesdisease managementanimal exploration traitsimmunityJournal article10.1093/jambio/lxad0941365-2672journal-article