The difficulty and expense of mitigating environmental heat stress makes it unrealistic for most feedlots. Therefore, producers would most benefit from nutritional and/or pharmaceutical strategies to manage the impact of heat stress on their animals. Our goal is to identify the most effective physiological targets for treatments that obtain the best possible outcomes for wellbeing and performance. To this end, the overall objective of the project is to determine the extent to which reducing inflammation associated with heat stress improves skeletal muscle growth and metabolic efficiency. Inflammatory factors are powerful regulators of muscle growth and metabolism, and their activity can be controlled by pharmaceutical and nutritional molecules. Greater inflammation is a mediator of heat stress, and understanding its role may lead to effective strategies for protecting heat-stressed livestock. We developed 2 specific objectives to this end. Objective 1. Mitigating the impact of heat stress on muscle growth & body composition by reducing inflammation. Objective 2. Mitigating the impact of heat stress on metabolic efficiency and wellbeing by reducing inflammation.