Climatic stress in pregnant sows: adaptive responses and effects on productivity

Abstract

The article presents data from the scientific literaturedescribing the influence of microclimate parameters on thebody of sows and their offspring. The key factors of thenormal course of physiological processes in the body of sowsand piglets are the optimal temperature, light, air velocity andhumidity. Sensitivity of sows to climatic factors increasessignificantly during pregnancy and lactation. At elevatedoutdoor temperatures, heat stress develops, which negativelyaffects well-being and productivity of sows and significantlyharms the offspring due to intrauterine temperature load. Itis established that there are differences in genetic tolerance to high temperature between different breeds of sows.Changes in physiological and behavioral parameters can beobserved at different stages of the reproductive cycle of sows.Pregnant sows respond to heat stress by increasing rectal andskin temperature, respiration rate and reducing their overallactivity. Elevated ambient temperature during late pregnancyincreases the catabolism of lipids and proteins in the bodyof sows, the concentration of adrenocorticotropic hormone,cortisol in the blood increases. Heat-exposed sows also havea shorter gestation period and a lower nest weight of pigletsat birth. During lactation, there are changes in general andfeed behavior, reduced feed intake and as a result, the processof milk production is disrupted. In particular, it was foundthat with increasing temperature from 20.0 to 29.0 °C milkproduction in sows decreases from 10.43 to 7.35 kg/day(p <0.05). The content of immunoglobulins, vitamins andmicroelements in milk decreases. This leads to a violation ofimportant physiological functions of the body of piglets andhas a negative impact on their growth and development. Themost critical periods for sows are the end of summer and thebeginning of autumn, when anestrus is observed, the rates offertilization, farrowing, fertility and weight gain of piglets arereduced. This is due to an imbalance in the hypothalamicpituitary-adrenal system and high levels of melatonin in theblood. The use of physiological and behavioral indicatorsis necessary to prevent climatic stress and increase animalproductivity. Key words: physiology, pigs, stress factors, thermoregulation, behavior, reproductive system, pregnancy, lactation.