There is never a time in swine production where producers aren’t facing challenges in some form or fashion. Many challenges – whether they are nutritional, health or management related – tend to be seasonal. Fall is typically a favorite season for many producers, lending optimized weather conditions for growth. But, hot summer temperatures bring on a distinct set of obstacles.
Heat stress, for example, is a concern in the summer – especially when hot temperatures are combined with high humidity. The optimal temperature for pigs post weaning is between 65°F and 75°F. In this temperature range, pigs remain in their thermoneutral zone. In the thermoneutral zone, swine can maintain their core body temperature without altering feed intake, behavior or metabolism. Body heat production is also at its lowest in this zone. When the temperature reaches beyond the upper range of the thermoneutral zone, pigs are unable to dissipate heat without expending extra energy. Instead, heat loss occurs through panting. Additionally, pigs may exhibit signs of heat stress, increasing water intake and reducing activity – including eating. There are also other physiological changes such as increased blood cortisol, increased oxidative stress, increased inflammatory cytokines, increased blood pH (respiratory alkalosis), alterations in intestinal microflora, reduction in blood flow to the intestines and other internal organs and loss of intestinal integrity. Ultimately, in addition to being a welfare issue, heat stress leads to economic loss from decreased performance, reduction in meat quality and increased mortality.
