The effect of floor type or relocation on calvesâ–™ pulsatile growth hormone and cortisol secretion
To examine if hard floor or relocation to a new room affects the pulsatile secretion of growth hormone (GH) and cortisol in calves, we housed individually 12 calves on concrete floors and 12 on rubber mats for 67â–“74 days. Half of the calves in each pen were relocated to an identical but strange room. Serial blood samples were taken 24 h prior to and 24 h following relocation at 20-min intervals and were assayed for GH and cortisol. Both of the hormones had a clear ultradian pulsatile variation. We detected (meanÂ±/se) 4.6Â±/0.6 GH pulses/24 h. GH concentrations peaked four times during the day and pulses were higher in daytime. Cortisol peaked 5.8Â±0.6 times/24 h. Cortisol concentrations were highest at feeding. No overall effects of flooring or relocation were found but calves on concrete floors had greater cortisol concentrations than on rubber mats, especially during the night.
Document Type: Research Article
Affiliations: 1: Research Centre for Animal Welfare, Faculty of Veterinary Medicine, University of Helsinki, Finland 2: Danish Institute of Agricultural Sciences, Tjele, Denmark 3: Pacific Agri-Food Research Centre, Agriculture and Agri-Food Canada, and the Animal Welfare Programme, University of British Columbia, Agassiz, BC, Canada
Publication date: 2006-11-01