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Biomarker responses to weaning stress in beef calves

O'Loughlin, Aran, McGee, Mark, Doyle, Sean, Earley, Bernadette
Research in veterinary science 2014 v.97 no.2 pp. 458-463
beef bulls, biomarkers, calves, interleukin-8, neutrophils, pastures, stress response, weaning
The study objective was to investigate the physiological effects of weaning on beef calves and identify a panel of blood-based welfare biomarkers. On the day (d) of weaning (d 0), 16 spring-born, single-suckled, beef bull calves that previously grazed with their dams at pasture, were assigned to one of two treatments: (1) control (n = 8), calves were loose-housed with their dam, (2) weaned (n = 8), calves were abruptly separated from their dam and loose-housed. Jugular blood was collected on d −4, 0, 1, 2, 3, 7, and 14 relative to weaning (d 0) and assayed for inflammatory and steroid variables. Total leukocyte counts were measured in whole blood. It is concluded that neutrophil number is a robust biomarker of stress and that plasma CXCL8 is a sensitive indicator of stress in weaned and control calves. In future studies, these two biomarkers should be central to the characterisation of stress responses.