Submitted to: Journal of Animal Science
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 9/12/2017
Publication Date: N/A
Citation: N/A Interpretive Summary: Measures of stress and metabolism have been shown to be indicative of growth and development of bovine respiratory disease (BRD) of beef cattle. It would be advantageous to be able to measure these markers earlier in life so that management strategies could be modified to improve production and wellbeing. This experiment was performed to determine if measurement of serum cortisol, lactate, and glucose prior to or at weaning would be predictive of average daily body weight gain (ADG) and development of BRD. Serum glucose at weaning tended to be predictive of lung lesions and cattle that were diagnosed with BRD tended to have lower pre-weaning glucose concentrations. Pre-weaning glucose was highly associated with pre-weaning and post-weaning ADG. The trend in the data likely indicates that calves that consume more milk prior to weaning grow slower after weaning. While stress measures early in life do not appear to be predictive of developing BRD, it does appear that glucose metabolism early in life can be predictive of growth potential of beef cattle.
Technical Abstract: The objectives of this experiment were to determine the association of circulating cortisol, lactate, and glucose early in life on ADG and incidences of bovine respiratory disease (BRD) in cattle in the feedlot. A blood sample was collected approximately 3 wk prior to weaning and at weaning from genetically diverse steers and heifers (n = 451). Cattle were weighed periodically throughout the study and ADG was calculated for the pre-weaning period, the receiving period, the finishing period, and total post-weaning ADG. Incidences of BRD were recorded and analyzed as a binary trait. Lung lesions were recorded at slaughter. Pre-weaning serum cortisol concentrations were positively associated (P = 0.040) with receiving ADG and explained 0.74% of the variance of receiving ADG. Pre-weaning glucose concentrations were positively associated (P < 0.001) with pre-weaning ADG and negatively associated with receiving (P = 0.003), finishing (P = 0.008), and total post-weaning ADG (P = 0.002) and explained 2.0% of the variance in total post-weaning ADG. Pre-weaning serum glucose concentrations could be indicative of milk consumption and therefore indicate calves receiving less milk grow slower prior to weaning, but experience compensatory gain post-weaning. Cattle that were diagnosed with BRD (n = 130) grew slower during the receiving phase (P = 0.004), but total post-weaning ADG was not different from cattle not diagnosed with BRD (P = 0.683). Additionally, cattle that were diagnosed with BRD in the feedlot tended to have slightly lower pre-weaning serum glucose concentrations (P = 0.062). Using a logistic regression analysis, none of the serum variables measured at or before weaning were predictive of developing BRD (P > 0.180). Weaning serum glucose concentrations tended to be predictive of the presence of lung lesions at weaning (P = 0.060). These data indicate that glucose measured early in life is associated with growth rate, and could indicate that carbohydrate metabolism could contribute to variation in ADG.