Phenotypic assessment of F0 generation lactating sows genomically selected for heat stress tolerance

作者：M.K. Byrd, Hui Wen, Pedro H F Freitas, J. Byrd, Francesco Tiezzi, Christian Maltecca, Yijian Huang, Ashley DeDecker, A. P. Schinckel, Luiz F. Brito, Jay S Johnson · 发表于：Journal of Animal Science · 年份：2025 · DOI：10.1093/jas/skaf205 · 被引用次数：6 · 研究领域：Animal Behavior and Welfare Studies、Effects of Environmental Stressors on Livestock、Animal Nutrition and Physiology

Genomic selection for greater HS tolerance (TOL) may enhance swine welfare under heat stress (HS) conditions. However, genomic selection for TOL based on variability in performance traits across environmental gradients tends to be genetically associated with reduced productivity. Therefore, the study objective was to biologically characterize genomic selection for TOL based on the rate of vaginal temperature (TV) change with rising environmental temperatures. Lactating sows (N = 26; Large White × Landrace; parity = 4.85 ± 0.75) divergently genomically selected for TOL (n = 14) or HS sensitivity (SEN; n = 12) in the F0 generation were subjected to cycling temperatures ranging from 28.90 to 30.23 °C from days 2.5 ± 1.0 post-farrowing to weaning (days 21.3 ± 1.1) across 4 repetitions. Indirect calorimetry was used to estimate total metabolic heat production (THP) on days 4, 8, 14, and 18 of lactation on an individual sow basis. Implanted data loggers measured TV daily in 15 min intervals. Respiration rate, skin temperature (ear, shoulder, rump, tail), sow posture, and waterer interactions were recorded daily at 0800, 1200, 1600, and 2000 hours. Sow feed intake (FI), waterer use, and non-nutritive drinker manipulation behaviors were measured daily. Litter weights were measured at birth, days 4, 8, 14, 18, and weaning. Data were analyzed with sow, litter, or sow + litter as the experimental units. Overall, TOL sows had greater THP/kg BW0.75 (P = 0.04; 5.68 ± 0.24 kcal/h/kg BW0.75)...