Heat stress in livestock due to climate change, impacting livelihoods

• Over 1 billion cows worldwide, including those in India, could experience heat stress by the end of the century due to high carbon emissions and insufficient environmental protection.
• Heat stress in livestock farming poses significant challenges and costs, potentially amounting to USD 1.7 billion in the US dairy industry alone.
• Reduction of emissions and limiting cattle expansion could mitigate heat stress impacts by 50-84% in various regions.
• The combination of high temperatures and excess moisture from climate change affects cattle fertility, growth, and even survival, impacting animal welfare and farm income.
• Swift action to decrease emissions and adapt livestock practices is crucial to safeguard cattle farming from the escalating threat of heat stress, potentially making cattle production less viable in many parts of the world.

Climate change impacts livestock farming, a major source of worldwide food production and impacted livelihoods. More than 1 billion cows around the world including India will experience heat stress by the end of the century if carbon emissions are high and environmental protection is low.

Heat stress in cattle

More than a billion cows worldwide will face heat stress by the end of the century if carbon emissions are high and environmental protection is low, according to new research published in the journal Environmental Research Letters from IOP Publishing.

In animal husbandry, heat stress is a massive issue that costs as much as USD 1.7 billion in the United States alone, mainly in the dairy industry. In tropical countries, it will become more challenging due to high emissions. However, reducing emissions and limiting cattle expansion could reduce impacts by 50-84%.

If carbon emissions remain high and environmental protection remains low, a new study suggests that more than 1 billion cows worldwide may experience heat stress by the end of the century.

Cow farming across most of the world, including Central America, tropical South America, Equatorial Africa, and South and Southeast Asia, would experience potentially catastrophic heat stress. The researchers also discovered that a rapid reduction in emissions while maintaining present cow production levels would reduce these impacts by at least 50% in Asia, 63% in South America, and 84% in Africa.

Animals across much of the world, including Central America, tropical South America, equatorial Africa, and South and Southeast Asia, would face deadly heatwaves.

Cutting emissions curbs cattle's impact

Researchers also found that reducing greenhouse gas emissions rapidly 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 up to 84 percent in Africa.

Extreme heat harms cattle in a number of ways, especially when it is combined with excess moisture. It reduces fertility, inhibits growth of calves and can lead to increased mortality. In lactating cows, it also reduces milk production. All of these affect the reality of animal husbandry farming, reducing animal welfare and farm income.

To study the current and future effects of heat stress on cattle, researchers from the Universities of Cape Town, KwaZulu-Natal and Chicago analyzed today's heat and moisture conditions around the world. They estimated how they would affect cattle in the future at different levels – emissions and land use type.

Researchers estimate that in the future, if carbon emissions are too high, nine out of ten cows worldwide will experience 30 or more days of heat stress per year. By the end of the century, more than three in ten cows will experience year-round heat stress. The most affected countries will be in tropical regions.

Many other parts of the world will also experience heat stress conditions for several months each year, including parts of Europe and North America. In some areas of Japan, Australia and Mexico, there will be 180 days or more of summer heat each year.

"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. It is also important to remember that we are only looking at heat stress here, and do not consider changes to water availability.

Dr Michelle North, veterinarian and researcher at the University of KwaZulu-Natal

"What this means, is that cattle farming will become less and less viable in many parts of the world.

Farmers must adapt to heat

Rising temperatures and humidity will force farmers to adapt to these new conditions by, for example, providing ventilation or even air conditioning for animals, or adopting heat-adapted cattle breeds.

But these measures will become more expensive with future temperature rise and may not be feasible in all places. This means animal husbandry will no longer be easy in places where it is currently a major occupation, for example in India, Brazil, Paraguay, Uruguay and north-eastern Argentina, and Sahelian and East African countries.

Rapidly cutting carbon emissions and maintaining livestock production within current levels would significantly reduce the number of cattle exposed to heat stress, especially in some of the most affected regions, including Asia, South America and Africa. Reducing emissions would also protect cattle in temperate regions from experiencing heat stress for more than half the year.

The researchers emphasize that the decisions made today will be important for decades to come. For example, cutting down tropical forests for livestock in areas such as the Amazon and central Africa will not only increase cattle numbers in areas that are already facing the most heat stress, but also exacerbate climate change. Due to which animal husbandry will become very difficult.

Solution: reduce emissions, adopt measures

Dr Christopher Trisos, ecologist and climate change researcher at University of Cape Town, said, "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."

"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.

"Reducing the amount of cattle products in diets can help limit future expansion of cattle farming, creating opportunities to protect and restore forests that can help limit future global warming."

Farmers can choose solutions based on how quickly they can be put in place and how well they work for cattle in coping with the heat. They might also think about using different kinds of cattle breeds that are better suited to local conditions.

"We've seen how climate change is affecting people through heatwaves, but the animals we raise for food are also in danger from these heatwaves," the researcher said. It's important for us to take action now to lessen this threat.

Expanding cattle farming by cutting down or burning tropical forests is not a good idea. It makes climate change worse and puts hundreds of millions of cattle at risk of heat stress all year round.

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