Cattle farming expansion could expose more than a billion cows to heat stress

A recent study published in the journal Environmental Research Letters has found that over one billion cows around the globe will experience heat stress by the end of this century if greenhouse gas emissions remain high and environmental protection low. 

Lethal heat stress 

The findings suggest that cattle farming would face potentially lethal heat stress in a variety of regions, including Central America, tropical South America, Equatorial Africa, and South and Southeast Asia. 

However, the analysis also revealed that rapidly reducing emissions – while keeping cattle production close to current levels – could reduce these impacts by at least 50 percent in Asia, 63 percent in South America, and 84 percent in Africa.

Heat impacts

Extreme heat is damaging to cattle in a variety of ways, especially when combined with high humidity. 

For instance, it reduces fertility, impairs the development of calves, reduces milk production in dairy cows, and can result in an increased number of deaths, thus significantly impacting the viability of livestock farming, while reducing animal welfare and farm income.

How the research was conducted

To examine current and future impacts of heat stress on cattle, the scientists analyzed today’s heat and humidity conditions around the world. 

Next, they estimated how these heat conditions will impact cattle in future decades by taking into account different levels of emissions and forms of land use.

What the researchers learned 

The investigations revealed that, if future emissions are very high, nine out of ten cows around the globe will experience 30 or more days of heat stress per year, and more than three in ten will experience it throughout the whole year by the end of the century. 

Although the most affected countries will be in tropical regions, many other parts of the world – including regions in Europe and North America – will face multiple months of heat stress each year. Some areas in Japan, Australia, and Mexico will likely experience over 180 heat stress days per year. 

Study implications 

Increasing temperatures and humidity will force farmers to adapt to these new conditions by providing ventilation or even air conditioning for the cattle or switching to heat-adapted cattle breeds. 

However, such measures will become increasingly expensive with future warming and will not be possible in all regions, meaning that cattle farming may no longer be viable in places where it is currently a major occupation, such as Brazil, India, Paraguay, Uruguay, north-eastern Argentina, and across East African and Sahelian countries.

“Our study clearly shows that cattle are increasingly exposed to temperatures that impact their welfare, reducing growth and production and potentially leading to increasing deaths, in many parts of the world that are currently seen as prime cattle-farming territory,” said lead author Michelle Worth, a veterinarian and researcher at the University of KwaZulu-Natal.

“It is also important to remember that we are only looking at heat stress here, and do not consider changes to water availability. What this means, is that cattle farming will become less and less viable in many parts of the world.”

Reducing emissions

Rapidly cutting greenhouse emissions and maintaining livestock production within current levels could significantly reduce the number of cattle exposed to heat stress, particularly in some of the most affected areas, such as Asia, South America, and Africa. 

Curbing emissions will also protect cattle in temperate regions from experiencing heat stress for over half a year.

Reducing meat consumption 

“At the same time, farmers and governments need to carefully consider whether it makes sense to expand cattle production in regions that are projected to become too hot for cattle,” said North. 

“Consumers can help by choosing not to support increasing investment in cattle farming, through their purchasing decisions (for example through choosing sustainable diets, reducing meat consumption and supporting local producers), and through their voting decisions.”

“We’ve seen the deadly impacts for humans of climate change intensifying heatwaves, but the animals that feed us are also at severe risk from heat. We need to act now to limit the risk,” said study senior author Christopher Trisos, an ecologist and climate change expert at the University of Cape Town.

“Expanding cattle production by cutting down or burning tropical forests is unsustainable, it worsens climate change and will undermine the welfare of hundreds of millions more cattle that will be exposed to severe, year-round heat stress.”

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By Andrei Ionescu, Earth.com Staff Writer

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