Jarvis Susan, D'Eath Richard B, Robson Sheena K, Lawrence Alistair B
Animal Behaviour and Welfare, Sustainable Livestock Systems, Scottish Agricultural College, West Mains Road, Edinburgh, EH9 3JG, UK.
Physiol Behav. 2006 Feb 28;87(2):345-52. doi: 10.1016/j.physbeh.2005.10.004. Epub 2005 Dec 5.
Commercial sows are typically confined in crates before and during parturition and remain there throughout lactation. In various animal species including non-lactating pigs, confinement over similar periods leads to adaptive changes in the HPA axis, consistent with chronic stress. To investigate evidence for chronic stress in lactating sows, primiparous sows (gilts) were kept in behaviourally confining crates with straw bedding (CS, n = 8) or without bedding (C, n = 8) or in larger strawed pens (PS, n = 16) between 5 days before parturition until 29 days postpartum (piglets were weaned on day 28). Behavioural and physiological recordings (Plasma ACTH and cortisol) were taken at intervals (baseline), and CRH injections were given on five occasions (days 2, 8, 15, 22 and 29 postpartum). The PS gilts spent more time in substrate-directed behaviour and lying ventrally, and less time lying laterally and sitting than the two crated treatments (C and CS) throughout lactation. Baseline plasma ACTH and cortisol levels showed no treatment differences, although we confirmed that a diurnal pattern exists, with morning (1000 h) cortisol being higher than later in the day. CRH challenge tests suggested changes in the HPA axis, consistent with chronic stress, by the end of the lactation period. Cortisol response to CRH tended to be higher in CS than PS across all days, and by day 29 cortisol response to CRH was significantly higher in CS compared to PS and tended to be higher in C than PS. Cortisol/ACTH ratio following CRH challenge also tended to be higher in the crate treatments (C and CS) by day 29. These data suggest that prolonged confinement in farrowing crates may have a negative impact on sow welfare.
商业母猪在分娩前和分娩期间通常被关在产栏中，并在整个哺乳期都待在那里。在包括非泌乳猪在内的各种动物物种中，在类似时期的限制会导致下丘脑-垂体-肾上腺（HPA）轴发生适应性变化，这与慢性应激一致。为了研究泌乳母猪慢性应激的证据，初产母猪（后备母猪）在分娩前5天至产后29天（仔猪在第28天断奶）期间被饲养在有稻草垫料的行为限制产栏（CS组，n = 8）或无垫料的产栏（C组，n = 8）中，或饲养在较大的有稻草的猪舍（PS组，n = 16）中。定期进行行为和生理记录（血浆促肾上腺皮质激素和皮质醇）（基线），并在五个时间点（产后第2、8、15、22和29天）注射促肾上腺皮质激素释放激素（CRH）。在整个哺乳期，PS组的后备母猪在指向垫料行为和腹卧方面花费的时间比两种产栏处理方式（C组和CS组）更多，而侧卧和坐立的时间更少。尽管我们证实存在昼夜模式，即早晨（1000 h）的皮质醇水平高于当天晚些时候，但基线血浆促肾上腺皮质激素和皮质醇水平未显示出处理差异。CRH激发试验表明，到哺乳期结束时，HPA轴发生了变化，这与慢性应激一致。在所有天数中，CS组对CRH的皮质醇反应往往高于PS组，到第29天，CS组对CRH的皮质醇反应显著高于PS组，且C组高于PS组。到第29天，CRH激发后的皮质醇/促肾上腺皮质激素比值在产栏处理方式（C组和CS组）中也往往更高。这些数据表明，在产仔栏中长期限制可能会对母猪福利产生负面影响。
