Longitudinal records of automatically-recorded vaginal temperature (TV) could be a key source of data for deriving novel indicators of climatic resilience (CR) for breeding more resilient pigs, especially during lactation when sows are at an increased risk of suffering from heat stress (HS). Therefore, we derived 15 CR indicators based on the variability in TV in lactating sows and estimated their genetic parameters. We also investigated their genetic relationship with sows’ key reproductive traits. The heritability estimates of the CR traits ranged from 0.000 ± 0.000 for slope for decreased rate of TV (SlopeDe) to 0.291 ± 0.047 for sum of TV values below the HS threshold (HSUB). Moderate to high genetic correlations (from 0.508 ± 0.056 to 0.998 ± 0.137) and Spearman rank correlations (from 0.431 to 1.000) between genomic estimated breeding values (GEBV) were observed for five CR indicators, i.e. HS duration (HSD), the normalized median multiplied by normalized variance (Nor_medvar), the highest TV value of each measurement day for each individual (MaxTv), and the sum of the TV values above (HSUA) and below (HSUB) the HS threshold. These five CR indicators were lowly to moderately genetically correlated with shoulder skin surface temperature (from 0.139 ± 0.008 to 0.478 ± 0.048) and respiration rate (from 0.079 ± 0.011 to 0.502 ± 0.098). The genetic correlations between these five selected CR indicators and sow reproductive performance traits ranged from − 0.733 to − 0.175 for total number of piglets born alive, from − 0.733 to − 0.175 for total number of piglets born, and from − 0.434 to − 0.169 for number of pigs weaned. The individuals with the highest GEBV (most climate-sensitive) had higher mean skin surface temperature, respiration rate (RR), panting score (PS), and hair density, but had lower mean body condition scores compared to those with the lowest GEBV (most climate-resilient). Most of the CR indicators evaluated are heritable with substantial additive genetic variance. Five of them, i.e. HSD, MaxTv, HSUA, HSUB, and Nor_medvar share similar underlying genetic mechanisms. In addition, individuals with higher CR indicators are more likely to exhibit better HS-related physiological responses, higher body condition scores, and improved reproductive performance under hot conditions. These findings highlight the potential benefits of genetically selecting more heat-tolerant individuals based on CR indicators.

中文翻译：

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根据热应激条件下自动记录的哺乳母猪阴道温度得出的新型气候适应力指标的遗传参数


自动记录的阴道温度（TV）的纵向记录可能是导出新的气候适应力（CR）指标的关键数据来源，以培育更具适应力的猪，特别是在哺乳期，此时母猪遭受热应激的风险增加。 HS）。因此，我们根据泌乳母猪TV的变异性得出了15个CR指标，并估计了它们的遗传参数。我们还研究了它们与母猪关键繁殖性状的遗传关系。 CR 性状的遗传力估计范围为 TV 下降率斜率 (SlopeDe) 的 0.000 ± 0.000 到低于 HS 阈值 (HSUB) 的 TV 值总和的 0.291 ± 0.047。对于五个 CR 指标，即 HS 持续时间 (HSD)、归一化中位数，观察到基因组估计育种值 (GEBV) 之间的中等到高度遗传相关性（从 0.508 ± 0.056 到 0.998 ± 0.137）和 Spearman 等级相关性（从 0.431 到 1.000）乘以归一化方差 (Nor_medvar)、每个个体每个测量日的最高 TV 值 (MaxTv) 以及高于 (HSUA) 和低于 (HSUB) HS 阈值的 TV 值之和。这五个CR指标与肩部皮肤表面温度（从0.139±0.008到0.478±0.048）和呼吸频率（从0.079±0.011到0.502±0.098）具有低到中度的遗传相关性。这五个选定的 CR 指标与母猪繁殖性能性状之间的遗传相关性范围为，活产仔猪总数为 - 0.733 至 - 0.175，出生仔猪总数为 - 0.733 至 - 0.175，生猪总数为 - 0.434 至 - 0.169。断奶仔猪数量。 GEBV 最高（对气候最敏感）的个体与 GEBV 最低的个体相比，平均皮肤表面温度、呼吸频率 (RR)、气喘评分 (PS) 和毛发密度较高，但平均身体状况得分较低。最具气候适应能力）。大多数评估的 CR 指标都是可遗传的，具有显着的加性遗传方差。其中五个，即 HSD、MaxTv、HSUA、HSUB 和 Nor_medvar 具有相似的潜在遗传机制。此外，CR指标较高的个体更有可能表现出更好的HS相关生理反应、更高的身体状况评分以及在炎热条件下改善的繁殖性能。这些发现强调了根据 CR 指标从基因上选择更耐热个体的潜在好处。