Roles of candidate genes in the adaptation of goats to heat stress: A review

The problem of heat stress (HS) in hot regions of the world is further complicated by climate change and the ensuing global warming. Goats have been a means of sustenance for rural dwellers and people found in resource-poor regions. Goats possess some phenotypic adaptive features that portray them as hardy with ecological adaptability based on anatomical, morphological and physiological characteristics that confer resistance to high environmental temperature. However, goat production is not insulated from the onslaught of climate change. Productivity declines in goats when exposed to HS. There is a rise in mortality and morbidity in heat-stressed goats. Responses of goats to high environmental temperature include perturbations in homeostatic milieu, reduced feed intake and utilisation, retarded growth, lowered immunity and reproductive efficiency. It becomes imperative to pay attention to their welfare under the harsh climatic vagaries envisaged in climate change. There are numerous inherent genetic endowments in goats all around the world that could be harnessed for better adaptation. Some of these genetic biomarkers include genes related to heat stress (HSF1, HSP20, HSP70, HSP90), growth (GH, GHR, IGF-1, LEP, LEPR, T3, T4, THR, NOS), reproduction (GnRH, GnRHR, FSHR, LHR, inhibin, PROGR, ESTR), and immunity (TLR2, TLR3, TLR8, TLR10, IL2, IL10). Of all these, HSP70 is the commonest genetic biomarker of thermotolerance in goats. Higher expression of HSP70 mRNA in tissues is an indication of higher thermotolerance. •Heat stress and global warming pose a great threat to goat production.•Goats’ well-being under the envisaged harsh climatic conditions must be addressed.•Numerous inherent genetic endowments could be harnessed for better adaptation.•Various candidate genes that could serve as biomarkers in goats are highlighted.•Of all these, HSP70 is the commonest genetic biomarkers of thermotolerance in goats.