400 Improving Heat Stress Resilience to Reduce the Negative Effects of pre- and Postnatal Heat Stress in Swine

Heat stress will become a more substantial issue for swine production as global temperatures continue to rise. Efforts have been made to mitigate the negative impacts of heat stress through advances in genetic selection, nutrition, precision technology, and management practices. However, heat stress is still a limiting factor to swine production that must be addressed. A key aspect to mitigating heat stress-related production losses in swine may be developing better management approaches and genetic selection techniques to improve heat stress resilience. This is especially true for heat stress sensitive populations such as gestating and lactating sows. Gestating and lactating sows are considered heat stress sensitive due to greater metabolic heat production resulting from fetal growth and milk production, respectively. Additionally, swine offspring are adversely affected by in utero heat stress, which imprints long-term negative phenotypes that reduce health and productivity regardless of environmental conditions. To address these concerns, swine producers have implemented a variety of cooling and management strategies to mitigate heat stress. However, the recommended or perceived heat stress temperature thresholds for implementation may not accurately reflect the thermal requirements of modern swine with current genetics or at variable gestation stages leading to ineffective use. As such, a re-evaluation of heat stress thresholds for modern swine is warranted. Additionally, genetic selection for productivity traits (e.g., litter sizes and lean growth) has increased metabolic heat production resulting in increased heat stress sensitivity. Therefore, the ability to perform large-scale measures of and implement heat stress tolerance traits within breeding populations may be advantageous for producers to improve heat stress resilience within their herds. Taken together, as heat stress becomes a greater issue for the swine industry, it will become increasingly important to develop sustainable approaches that improve swine heat stress resilience while maintaining or improving producer profitability.