泽西牛犊对热胁迫的生理应答及其作为动物福利下降指标的潜在应用性

本研究以泽西奶牛(Bostaurus)牛犊为对象,探讨温、热环境(30℃)下短暂暴露是否影响其体温、心跳和呼吸频率以及细胞和内分泌应激反应(皮质醇、甲状腺激素、牛生长激素及热应激蛋白72)。结果表明:热暴露导致呼吸频率和心率加快,体温显著升高,但幅度较小。在所研究的细胞和内分泌应激反应中,血浆甲状腺激素浓度略下降,肌肉热应激蛋白72的浓度稍增加。因此,尽管夏季饲养动物所经历的较高环境温度(但非极端温度)能影响泽西牛犊的生理,但是泽西牛犊能对温和的暂时性环境温度改变做出适应性反应。我们认为,直肠温度和细胞热应激蛋白72浓度是所研究参数中评价热胁迫降低动物福利的最适指标。

Physiological responses to heat stress and their potential use as indicators of reduced animal welfare in Jersey calves

In this study we used calves of the Jersey dairy cattle breed Bos taurus to investigate if body temperature, heart and respiration rates and the cellular and endocrine stress responses (cortisol, thyroid hormones, bovine growth hormone and heat shock protein 72) are affected by temporary exposure to a moderate heat load (30℃). The results show that exposure to heat causes increased respiration rates, a slight but significant increase in body temperatures and increased heart rates. Of the cellular and endocrine stress responses investigated thyroid plasma hormone concentrations were slightly reduced and muscle Hsp72 concentrations were slightly increased by exposure to heat. The results reveal that high but nonextreme ambient temperatures often encountered by farm animals during summer impacts on the physiology of Jersey calves, but also that Jersey calves seem to be capable of responding in an adaptive manner to moderate and temporary ambient temperature changes. Of the investigated parameters we advocate that rectal temperature and cellular Hsp72 concentrations are the most appropriate indicators of reduced animal welfare in consequence of heat stress exposure Acta Zoologica Sinica 52 (4): 681-689, 2006].