Increases in extreme heat stress in domesticated livestock species during the twenty‐first century

Abstract

Anthropogenic climate change is expected to have major impacts on domesticated livestock, including increased heat stress in animals in both intensive and extensive livestock systems. We estimate the changes in the number of extreme heat stress days per year for animals raised outdoors that can be expected in the major domesticated animal species (cattle, sheep, goats, poultry, and pigs) across the globe during this century. We used the temperature humidity index as a proxy for heat stress, calculated using temperature and relative humidity data collated from an ensemble of CMIP6 climate model output for mid and end century. We estimate changes in the proportions of different livestock species that may be at increased risk of extreme heat stress under two contrasting greenhouse gas emission scenarios. Results are discussed in relation to changes in the suitability of different climate conditions for domesticated livestock during the current century. We find that by end century, extreme heat stress risk is projected to increase for all livestock species in many parts of the tropics and some of the temperate zones, and to become climatically more widespread, compared to 2000. Although adaptation options exist for both intensive and extensive livestock production systems, the increasing pervasiveness of extreme heat stress risk in the future will seriously challenge the viability of outdoor livestock keeping, particularly in the lower latitudes in lower and middle‐income countries where the costs of adaptation may be challenging to address.

The Genetics of Thermoregulation in Pigs: A Review

“…Furthermore, there are short-term responses to HS [acclimation or acclimatization ( 21 )] that differ from long-term ones (adaptation). In addition HS varies in duration (short periods of HS, heat waves of few days' duration or chronic HS) and magnitude (moderate, high, or extreme) ( 30 ). The improvement of thermoregulation in pigs by genetic selection assumes that there is a genetic component of traits associated with thermoregulation.…”

Consistent cooling benefits of silvopasture in the tropics

“…Hence, agroforestry may be a key component of approaches to reduce heat-related negative health outcomes in rural tropical areas. In addition, cooling services also extend to livestock in these regions, as excess heat loads can decrease productivity, growth, and reproduction, and increase vulnerability to disease 28 – 30 . The importance of cooling services are increasingly clear given recent work highlighting humid heat impacts on factors such as labor may be underestimated 44 .…”

“…We focus specifically on silvopasture for three reasons. First, extreme heat stress is expected to increase in many parts of the tropics and temperate zones not just for people but for all major domesticated animal species 28 , negatively impacting livestock production 29 , 30 . Second, regulation of temperature for both livestock and people has been identified as a potentially important benefit of silvopasture 14 , 31 , and third, pasturelands are often targeted by initiatives to expand tree cover 4 , 32 .…”

Effect of Different Pig Fecal Microbiota Transplantation on Mice Intestinal Function and Microbiota Changes During Cold Exposure

“…The thermoneutral zone for most mammals varies with age and body weight ( 2 ). For young growing pigs, this is particularly important as they lack significant sources of adipose at birth and do not develop these stores until maturity ( 3 ). Thermal stress imposed by fluctuations in environmental temperature affects animal physiological, biochemical, and molecular signal regulation ( 4 , 5 ).…”