The effects of acute stress on sow reproductive performance are well established, but we know less about the implications of chronic stress for sow performance. This study investigated associations between total skin lesion counts 24hr and 3 weeks post-mixing, hair cortisol concentrations at the end of pregnancy, and reproductive performance of sows. Sows (n = 264; parity 1-5) were artificially inseminated and locked into individual feeding stalls within 11 fully slatted gestation pens, immediately after service. Sows were released from the stalls at approximately 25 days post-service, allowed to mix, and thereafter had free access to the stalls. Skin lesions were counted 24hr post-mixing (i.e. one day after release from the stalls), and 3 weeks post-mixing on the anterior (head, neck, shoulders and front legs), middle (flanks and back), and posterior (rump, hind legs and tail). The sum of counts across all sites yielded a total skin lesion count for each sow. Back fat depth measurement and hair collection were carried out one week prior to farrowing. Sow reproductive performance measures included the number of piglets born alive, born dead, mummified, and total born. Piglets from 75 sows were tagged, weighed and scored for vitality (0 = least vital, to 4 = perfect) and intra-uterine growth retardation (IUGR; 0 = none, to 3 = severe). There was a positive association between total skin lesion counts 3 weeks post-mixing and both the number of mummified piglets (P = 0.045), and IUGR scores (P = 0.018). There was no correlation between total skin lesion count either 24hr (Rho = 0.10; P > 0.05) or 3 weeks post-mixing (Rho = -0.02; P > 0.05) and hair cortisol concentrations. There was also no association between hair cortisol concentrations and measures of sow reproductive performance (P > 0.05). Higher skin lesion counts 3 weeks post-mixing were associated with aspects of sow reproductive performance. This suggests that chronic stress caused by sustained aggression had a negative impact on the reproductive system. Nevertheless, given the lack of significant associations between hair cortisol, skin lesion counts, and measures of reproductive performance, this was not supported by the findings for hair cortisol.

急性应激对母猪生殖性能的影响已得到充分证实，但我们对慢性应激对母猪性能的影响了解较少。这项研究调查了混合后24小时和3周的总皮损计数，妊娠结束时毛发皮质醇浓度与母猪生殖性能之间的关系。母猪（ñ = 264; 人工授精后立即人工授精并锁定在11个完全板条的妊娠围栏内的单个饲养隔间中。服役后约25天，母猪从摊位中释放出来，进行混合，然后可以自由进入这些摊位。混合后24小时（即从摊位释放后一天）和混合前3周（前，头，颈，肩和前腿），中部（后腹和臀部）和后部（臀部）对皮肤病变进行计数，后腿和尾巴）。所有位点的总计数得出每头母猪的总皮肤病灶数。分娩前一周进行背脂深度测量和头发收集。母猪的生殖性能指标包括活着的仔猪数量，死亡的仔猪数量，木乃伊的仔猪数量和总出生的仔猪数量。对75头母猪的仔猪进行了标记，对生命力（0 =最不重要，至4 =完美）和子宫内发育迟缓（IUGR； 0 =无，至3 =严重）进行权衡和评分。混合后3周的总皮损计数与木乃伊仔猪的数量之间呈正相关（P  = 0.045）和IUGR得分（P  = 0.018）。混合后24小时（Rho = 0.10；P > 0.05）或3周（Rho = -0.02；P > 0.05）与总皮损浓度之间没有相关性。头发皮质醇浓度与母猪生殖性能的指标之间也没有关联（P> 0.05）。混合后3周较高的皮损计数与母猪生殖性能有关。这表明持续侵略引起的长期压力对生殖系统有负面影响。但是，由于在头发皮质醇，皮肤病灶数和生殖能力之间缺乏显着关联，因此头发皮质醇的发现并不能支持这一点。