Physiological temperature response and embryonic mortality in stressed swine

Area of Science:

• Reproductive Physiology
• Animal Science
• Environmental Stressors

Background:

• Heat stress negatively impacts livestock productivity and welfare.
• Early gestation is a critical period for embryonic development and survival in pigs.

Purpose of the Study:

• To investigate the physiological and reproductive effects of short-term heat stress during early pregnancy in female pigs.
• To determine the impact of elevated temperatures on embryonic mortality and fetal development.

Main Methods:

• Two trials exposed mated female pigs to high ambient temperatures (approx. 40°C) during specific early gestation periods (days 2-13 and 14-25).
• Physiological parameters (rectal temperature) and reproductive outcomes (embryonic mortality, fetal degeneration) were monitored.

Main Results:

• High thermal exposure significantly increased rectal temperatures in treated pigs.
• Stressed pigs showed increased activity and erratic behavior at elevated body temperatures.
• Embryonic mortality was higher in heat-stressed pigs, with a significant proportion of litters containing degenerating fetuses.

Conclusions:

• Short-term heat stress during early gestation adversely affects pig reproductive function.
• Thermal stress can lead to increased embryonic/fetal loss, with potential for delayed or continuous detrimental effects on embryo survival.