Short communication: Hair cortisol concentrations in Holstein-Friesian and crossbreed F_1 heifers

摘要

The aim of this study was to evaluate the hypotha-lamic-pituitary-adrenal (HPA) axis activity of Holstein-Friesian and crossbreed F_1 heifers by analysis of the cortisol concentrations in hair samples. Cortisol, the primary hormone of the HPA axis, is the biological end-point for the investigation of the HPA response. The study was conducted on 290 prepubertal heifers; 142 heifers were pure Holstein-Friesian and 148 were crossbreed F_1 heifers obtained from the 3-way rotational system with Swedish Red and Montbeliarde breeds. Extraction was performed on the hair using methanol, and cortisol concentrations were determined by a ra-dioimmunoassay method. Cortisol concentrations measured in regrown hair of crossbreed F_1 heifers were significantly lower than those in hair of Holstein-Friesian heifers. This result helps us to better understand the differences in HPA activity and allostatic load between Holstein-Friesian and crossbreed F_1 heifers and allows us to better assess the adaptability of these animals to the environment and the importance of crossbreed traits for profitability in dairy farming.