Bioenergetic Consequences of Pre- and Post-Natal Heat Stress on Swine Productivity.

Heat stress decreases the sustainability and profitability of global swine production and the reductive effects of pre- and post-natal heat stress on pig productivity have been well described. Decreased growth performance and sow milk production during heat stress exposure is generally attributed to reduced energy consumption and a corresponding catabolic state. Moreover, an assumed increase in maintenance costs due to energetic requirements for thermoregulation and greater chemical reaction rates is proposed to reduce energy available for growth and lactogenesis leading to decreased efficiency and productivity. Despite this, recent research has determined that postnatal heat stress can directly impact nutrient partitioning priorities and growth rate independent of energy intake, maintenance costs may be reduced in heat stressed pigs relative to thermoneutral controls, and that heat stress may have a direct negative effect on sow milk production and litter growth performance independent of sow energy intake. In addition to the postnatal consequences of heat stress, prenatal heat stress reduces postnatal growth rate and feed efficiency in pigs independent of the postnatal environment, increases fasting heat production during the growing phase, and alters nutrient partitioning priorities during the finishing phase leading to an increase in adipose tissue accretion at the expense of lean accretion. Furthermore, meat quality and quantity may be negatively impacted by prenatal heat stress exposure. In summary, both preand postnatal heat stress exposure elicit bioenergetic changes in pigs that influence postnatal productivity, and mitigating heat stress is and will likely continue to be a priority for the swine industry. [ABSTRACT FROM AUTHOR]