Biomarker responses to weaning stress in beef calves

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. (C) 2014 Elsevier Ltd. All rights reserved.