The Genetics of Thermoregulation in Pigs: A Review

Abstract

Heat stress (HS) affects pig performance, health and welfare, resulting in a financial burden to the pig industry. Pigs have a limited number of functional sweat glands and their thermoregulatory mechanisms used to maintain body temperature, are challenged by HS to maintain body temperature. The genetic selection of genotypes tolerant to HS is a promising long-term (adaptation) option that could be combined with other measures at the production system level. This review summarizes the current knowledge on the genetics of thermoregulation in pigs. It also discusses the different phenotypes that can be used in genetic studies, as well as the variability in thermoregulation between pig breeds and the inheritance of traits related to thermoregulation. This review also considers on-going challenges to face for improving heat tolerance in pigs.

Influence of housing air temperature on the behavioural acts, physiological parameters, and performance responses of fattening pigs

“…The authors also noted that the maximum time that pigs can lying is related to the time that pigs must get up to perform water intake and the act of defecation or urination, which occurs approximately once every 41 minutes (Aarnink et al 1996;Nielsen et al 1996) although in our study, the time spent on the act of defecation and urination of fattening pigs was not recorded. The time feed intake (P < 0.01) in the pigs of the 3rd experimental group a significant decreased compared to the 1st control animals, which is consistent with previous studies (Parois et al 2018;Rauw et al 2020;Gourdine et al 2021). A decrease in feed intake indicates a reduction in productivity due to heat stress in pigs (Ross et al 2015).…”

“…Breathing becomes more frequent, and there is a refusal to feed; a coma quickly sets in and even death. Adult pigs are more tolerant of low temperatures (Gourdine et al 2021).…”

“…The climate of the south of Ukraine, particularly the Odesa region, is characterized by temperate continental with mild winters with little snow and especially hot summers. Therefore, with deviations of microclimatic parameters in housing for keeping pigs (Gody et al 2020), there are technological stresses can occur, affecting the change in behavioural acts, reducing performance responses, health and welfare of pigs (Nienaber and Brown Brandl 2009;Lacetera 2019;Gourdine et al 2021). In this regard, we emphasize that obtaining high-quality pork is impossible without ensuring the normalized indicators of microclimatic parameters, even with full feeding.…”

Welfare of pigs during transport

“…As reviewed by Gourdine et al. (2021) and Mayorga et al. (2019), there is growing evidence that genetic selection has reduced pigs’ ability to cope with heat stress, due to an increase of metabolic heat production with the improvement in reproductive traits and lean tissue growth rate, at the expense of adaptive capacities.…”

Trehalose Attenuates Oxidative Stress and Endoplasmic Reticulum Stress-Mediated Apoptosis in IPEC-J2 Cells Subjected to Heat Stress

“…The increasing risk of high ambient temperatures, due to the worsening of climate warming, causes heat stress (HS) in human beings and livestock, affecting health and development. Specifically, pigs are faced with greater challenges under heat exposure due to their limited sweat glands for heat dissipation and high metabolic heat production [ 1 , 2 ]. Heat stress leads to reduced performance, poor meat quality, and increased morbidity and mortality, all of which cause economic losses for the pig industry [ 3 ].…”