Depending on how the pig adapts to stress, it may have a deleterious effect or it could be an instrument of training and hardening. Milk yield in nursing sows is decreased and piglet growth slower. High temperatures in early pregnancy can cause embryonic death and delay sexual maturity in gilts.
Heat stress has negative effects on sperm production in boars.
Decreased fertilization and litter size may show up as a problem after a period of hot weather. Feeder pigs suffering from heat stress also do not eat as well and growth rates slow down. Longer days to market and barn throughput can be the results in feeder operations. Transportation Stress Market hogs are susceptible to stress at marketing time as they are moved from pen to truck, mixed with other pigs, often crowded and heat stressed. Some strains of pigs succumb to over-exertion at this time.