Direct and indirect contributions of molecular genetics to farm animal welfare: a review

Abstract

Since domestication, farm animals have played a key role to increase the prosperity of humankind, while animal welfare (AW) is debated even today. This paper aims to comprehensively review the contributions of developing molecular genetics to farm animal welfare (FAW) and to raise awareness among both scientists and farmers about AW. Welfare is a complex trait affected by genetic structure and environmental factors. Therefore, the best welfare status can be achieved not only to enhance environmental factors such as management and feeding practices, but also the genetic structure of animals must be improved. In this regard, advances in molecular genetics have made great contributions to improve the genetic structure of farm animals, which has increased AW. Today, by sequencing and/or molecular markers, genetic diseases may be detected and eliminated in local herds. Additionally, genes related to diseases or adaptations are investigated by molecular techniques, and the frequencies of desired genotypes are increased in farm animals to keep welfare at an optimized level. Furthermore, stress on animals can be reduced with DNA extraction from stool and feather samples which reduces physical contact between animals and veterinarians. Together with molecular genetics, advances in genome editing tools and biotechnology are promising to improve FAW in the future.

Conservation and Selection of Genes Related to Environmental Adaptation in Native Small Ruminant Breeds: A Review

“…Internal factors include animal activities and housing conditions, such as management and feeding practices, whereas the external factors consist of stressors outside of the barn condition, such as heat waves, drought, and forage deficiency [24,25]. Environmental stress factors occur when a given animal's environment changes and shows enormous diversity in terms of their severity and duration [26]. A stress may be chronic, such as in high stocking density situations and unsuitable barn design and construction that will evoke sustained and prolonged discomfort in herds one generation after another, or acute, as in the negative effects of transportation stress, which is abrupt, profound, and sustained over a short time period [27].…”

“…Environmental stressors due to climate change are the most important ecological factors determining the growth, development, and productivity of domestic animals [29]. Whether caused by natural phenomena or by human activities [28], the repercussions of climate change are not just limited to a significant decrease in livestock welfare and wellbeing [26], but will also have a negative impact on the environmental ecology through reducing pasture and water availability, and also with the potential introduction of new diseases and parasites [30].…”

“…Climate change, in addition to an increase in global warming, also manifests in an increase in frequency in extreme weather events and conditions, such as unexpected and unpredictable rainfall patterns, drought, and heat waves. The gradual yearly increase in ambient temperatures is being reported as causing particular damages to the thermal comfort zone in farm animals [26,28]. Under normal environmental conditions, livestock maintain a balance between heat gain and heat loss, a physiological process referred to as thermoregulation.…”

“…An increase in heat load mainly occurs due to the heat increment associated with metabolic activities and exposure to high ambient temperature. Heat-stressed animals will consume less feed and drink more to compensate for metabolic heat production, and they will also move to avoid direct exposure to sun while seeking air flow to facilitate heat dissipation [26,30]. Although these responses may lessen the negative effects of heat stress, they are associated with a decrease in production and reproductive efficiency in small ruminants, particularly due to low feed intake [33].…”

HSP90AB1 (SNP-4338T>C) gene polymorphism associated with thermo-tolerance in some cattle breeds in Türkiye

“…The Intergovernmental Panel on Climate Change (IPCC) has documented that the increase in temperature is expected to be 2-3ºC higher at the end of the 21 st century (Lu et al 2020;Malhi et al 2021;UNEP 2022). As highlighted by Demir et al (2022a), climate change is considered to be a major threat to the sustainability of animal breeding systems across the globe since increased temperature not only negatively affects animal welfare but also leads to reproduction problems and a decrease in economically important yields (Demir et al 2021a).…”