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Interpretive Summary: Behavioral and stress responses to feeding time in pregnant sows

By: Anne Kamiya, MS

Feeding time can directly impact sow performance and stress levels. Depending on the time of day and length of time animals are fed, physiological and behavior changes may occur. How such changes impact animal welfare and performance, however, are poorly understood.

In this recent Journal of Animal Science study, researchers evaluated how feeding time affected the stress response and behavior of pregnant sows. They monitored feed anticipatory activity (FAA), total activity, feeding rate and saliva cortisol levels of sows fed at three different times under isocaloric conditions. It was hypothesized that behavior and hormones associated with the hypothalamic–pituitary–adrenal (HPA) axis would be impacted by feeding sows at different times of the day. 

Pregnant sows were fed a corn-soybean meal-based diet at one of three different times (0730, 1130 or 1530 hours) for 28 days. Sows fed at 0730 were designated as the control group. Activity, feeding behavior and cortisol hormone levels were monitored throughout the study. Sows fed at 1130 had the lowest cortisol levels and highest FAA, total and feeding activity, compared to sows fed at 0730 and 1530. Sows fed at 0730 had the lowest FAA, total activity and feeding activity, but cortisol levels were similar to sows fed at 1530. Sows fed at 0730 exhibited reduced behavioral stress responses. The authors concluded that increased activity may not correlate to (cortisol-related) stress levels from feeding at different times. 

Overall, the results of this study suggest that feeding pregnant sows at different time periods does have an impact on their behavior. How such changes might impact animal welfare and performance, however, are yet to be elucidated. More studies into the connection between feeding time and stress responses of pregnant sows is justified. 

The original article, Behavioral and stress responses to feeding time in pregnant sows under limit-fed regime, is now available in the Journal of Animal Science.