Interpretive Summary: Thermoregulatory and physiological responses of nonpregnant, mid-gestation, and late-gestation sows exposed to incrementally increasing dry bulb temperature
By Anne Zinn
It is believed that gestating sows may be more susceptible to increasing dry bulb temperatures due to greater metabolic heat production and increased body mass, especially as gestation advances, but there are very few studies exploiting the thermoregulatory and physiological responses of sows at differing gestation stages exposed to gradually increasing temperatures. Therefore, a study recently published in the Journal of Animal Science aimed to determine the thermoregulatory and physiological responses of sows with current genetics exposed to increasing environmental heat load at three reproductive stages: nonpregnant, mid-gestation, and late-gestation. The research team hypothesized that late-gestation sows would have a more sensitive thermoregulatory and physiological response to increasing environmental heat load relative to mid-gestation and nonpregnant sows.
Results of the present study demonstrated that, when compared with mid-gestation and nonpregnant sows, late-gestation sows had increased respiration rate and altered blood characteristics in response to increasing dry bulb temperature, which can be indicative of greater heat stress sensitivity. However, minimal differences between mid-gestation and nonpregnant sows were detected in thermoregulatory and physiological responses to increasing dry bulb temperature.
The results of this study provide evidence that late-gestation sows should be managed differently during times of heat stress as they may succumb to heat stress at lower dry bulb temperature when compared with mid-gestation and nonpregnant sows. Further research is warranted to investigate interventions to reduce the negative impact of heat stress during gestation as well as to elucidate the sow’s response to long-term changes in dry bulb temperature.
The full paper can be found on the Journal of Animal Science webpage.