Characterizing the effects of gestational heat stress on reproductive efficiency and thermoregulation in replacement gilts divergently selected for thermotolerance in the F1 generation

作者：MaryKate H Byrd, Luiz F. Brito, J Musa, Shelby L Diggs, L Kirsten Senn, Hui Wen, Pedro H F Freitas, John L Byrd, Francesco Tiezzi, Christian Maltecca, Yijian Huang, A. P. Schinckel, Jay S Johnson · 发表于：Journal of Animal Science · 年份：2025 · DOI：10.1093/jas/skaf353 · 被引用次数：3 · 研究领域：Effects of Environmental Stressors on Livestock、Animal Behavior and Welfare Studies、Reproductive Physiology in Livestock

This study evaluated whether genomic selection for heat stress tolerance (TOL) in gilts improved thermoregulatory responses and reproductive and litter outcomes when compared to heat stress sensitive (SEN) gilts. An F0 sow population was previously identified based on genomic breeding values for TOL and SEN. In this study, F1 TOL (n = 15) and SEN (n = 13) gilts (Large White × Landrace) were bred to TOL or SEN Landrace boars. Pregnant gilts were housed individually and exposed to thermoneutral (TN; 21.46 ± 2.92°C; n = 7 TOL and 6 SEN) or cyclic HS (26 to 36°C; n = 8 TOL and 7 SEN) from gestation d 6.3 ± 0.9 to 65.3 ± 0.9 (ETP), then TN (21.40 ± 3.13°C) until farrowing (LGP). Gilts were limit-fed 1.82 kg/d with ad libitum water access. Vaginal temperature (TV) was recorded every 10 min, respiration rate (RR) was measured at 0800 and 1500 h, and body weight was measured weekly. Hair cortisol was measured on d 3.3 ± 0.9 and 67.3 ± 0.9 of gestation. The number of liveborn, stillborn, and mummified piglets was recorded. Placenta samples were collected (n = 1 male and 1 female per litter) to assess placental 11β-hydroxysteroid dehydrogenase-2 (11β-HSD2) and cortisol concentrations. Data were analyzed as a 2 × 2 factorial with experimental units as either gilt or individual piglet. Vaginal temperature was greater (P < 0.01; 0.31°C) in HS versus TN gilts and tended to be reduced (P = 0.06; 0.10°C) in HS+TOL versus HS+SEN gilts. Respiration rate increased (P < 0.01; 20 bpm) in HS versu...