April 12, 2020

Interpretive Summary: Feed removal in pigs recovering from acute hyperthermia

Interpretive Summary: Effects of feed removal on thermoregulation and intestinal morphology in pigs recovering from acute hyperthermia

By: Anne Wallace

Heat stress negatively impacts animal welfare, meat quality and productivity. Various external strategies to mollify heat stress in pigs have been engineered, however, acute heat stress and is still problematic. Heat stress also injures the intestines of pigs, leading to potential poorer health outcomes than pigs that were not heat stressed.

Rapid cooling of pigs suffering from acute hyperthermia (dousing in water and housing in an environment conductive to regaining normal temperature) has so far shown mixed results. Body temperature increases with the consumption of feed. Therefore, it is plausible that the interaction between heat stress and feeding may have impacts on the effectiveness of rapid cooling. 

The authors of this March 2020 Journal of Animal Science article evaluated whether feeding during rapid cooling could possibly elucidate the reasons for inconsistencies in past studies on rapid cooling.  They hypothesized that withholding feed would help pigs recover faster.

Pigs were fed ad libitum or had food withheld during a three-hour rapid cooling period, following three hours of acute heat stress. Control pigs not exposed to heat stress were also evaluated under the same feed conditions. Although gastrointestinal temperatures returned to normal more rapidly when feed was withdrawn during rapid cooling, there was no difference in post-heat stress intestinal injury between pigs which were fed versus those that had feed withheld. Additionally, no significant differences in vaginal or skin temperatures of any of the feed groups were noted.

Overall, the results of this study suggest that withholding feed during rapid cooling impacts how fast gastrointestinal tract temperature normalizes in heat stressed pigs. However, the benefits of withholding feed on gastrointestinal injury post-heat stress was not apparent in this study. More in-depth studies looking at how feed and other factors might impact gastrointestinal recovery from acute heat stress in pigs is justified.