Study: Cows and other livestock with stomach problems can exacerbate global warming.

A new study has found that cattle with stomach problems may be a big problem with the climate,media reported. This is because cattle and other livestock with worms and other parasites produce more super-powerful greenhouse gas methane than healthy animals. Methane plays a role in warming the planet 28 to 36 times as much as carbon dioxide.

Study: Cows and other livestock with stomach problems can exacerbate global warming.


The U.N. Food and Agriculture Organization estimates that methane from cattle and other livestock will increase by 20 percent between 2017 and 2050. But according to a new paper published today in Trends in Ecology and Evolution, the increase in methane could be as high as 82 percent if parasite infections are also taken into account.

This is a big difference, especially given the extent to which domesticated livestock have contributed to climate change. Livestock account for 60 per cent of all mammalian biomass on the planet, and livestock are responsible for more than 14 per cent of human greenhouse gas emissions. By contrast, aviation accounts for only about 2% of global emissions.

More worryingly, there may be a dangerous feedback loop between climate change, parasitic diseases and higher methane emissions: animals infected with parasites and bacteria release more methane in their lifetimes, accelerating climate change. Parasites infected with livestock can breed at warmer temperatures, infect more animals and thus continue the vicious cycle.

“It could be a very interesting phenomenon, or it could be an important phenomenon that we didn’t really think about,” said Vanessa Ezenwa, lead author of the study and a professor of ecology at the University of Georgia.

With or without infection, cattle and other hoofed herbivores known as ruminants are the animals that emit the most methane. Other animals, including humans, also release methane, but ruminants have four cavities in their stomachs, which release more methane. They have a space for whole fermented foods, where microbes that help them digest hard food produce large amounts of gas that heat the earth.

Parasitic infections can lead to many changes that can increase methane emissions from livestock. These animals grow more slowly, which leads to more lifetime emissions because they take longer to develop enough heads for human slaughter. Infection also reduces milk production and the efficiency of dairy farming. Ranchers may decide to slaughter and replace their cattle more frequently, and evidence suggests that this usually leads to more emissions rather than less.

In the most extreme cases proposed in the paper, methane emissions from livestock would increase by 52 percent globally if each animal became ill, the study authors note. To calculate this number, Ezenwa and her colleagues reviewed existing studies on the effects of parasitic infections on methane production in specific animals. They used the findings to calculate the potential global impact of methane emissions. Data from the United Nations Food and Agriculture Organization serve as a benchmark for the study.

But there are limitations to the study, which provides estimates rather than exact numbers. The researchers used variable rates of potential infections because they did not have a real global rate of parasitic infections. Actual data may vary widely from region to region and there are data gaps.

Ermias Kebreab, director of the World Food Center at the University of California, Davis, said the results of the new study were not necessarily surprising. Kebreab was not involved in the study. “It’s common sense,” he said.

Kebraeb noted that the study could be most helpful in low- and middle-income countries, which are more common for parasitic infections. North America and Europe have increased livestock production by better controlling pathogens, he said. “It’s a great article that helps us remember that there’s a compound problem.”

Parasites that cause trouble for cows grow outside before infecting the host. Ezenwa says some worms need warmer temperatures to thrive. She says the parasites have more time to develop and infect livestock as climate change makes winters warmer and summers longer in some areas.

Ultimately, the new study provides the information needed to do more research to respond to the climate crisis. This may bring a range of benefits: healthier animals and healthier worlds, thus creating a better living environment for our people.