The role of phenotypic and genetic basis of livestock selection for climate change adaptation and mitigation: A review

Livestock are not only suffering from climate change, but also contribute to climate change through the direct and indirect release of greenhouse gases (CH4, N2O and CO2). Characterization, identification and conservation of heat tolerant livestock breeds are basics for future challenging climate. Properties of the skin, hair, coat color, coat type, sweating, respiration capacity, tissue insulation, surface area relative to body weight, endocrinological profiles and metabolic heat production are important factors involved for heat tolerance. Selection based on these phenotypic characteristics is play indispensible for climate change adaptation and mitigation.  Molecular information is used to know the candidate gene for heat tolerance, their action, specific function and location on chromosomes thereby important for modification of gene and selection of heat tolerant breed and feed efficient animals. Genomic information also used to identify genes that regulated during a stressful event can lead to the identification of animals that are genetically superior for coping with stress. Marker assisted selection and proteomics may also be valuable in selection for secondary traits linked to adaptation, such as the genes for high levels of blood urea and ruminal ammonia in certain genotypes, associated with adaptation to low-quality C4 grasses. Scientific research results demonstrated that heat tolerance is heritable trait and variable between/within livestock breeds, thereby variation and heritability of the trait opens the window for selection of heat tolerant animals. Therefore, the combined genomic selection using genome wide DNA markers that predict tolerance to heat stress and phenotypic selection could be accelerated breeding of highly productive and heat tolerant livestock breeds. Further research should be conducted on characterization, identification of indigenous breeds at molecular level and on identification of responsible genes/genomic regions associated with thermoregulation, feed and production efficiency in order to develop suitable adaptive and mitigation strategies to counter environmental stresses.