Livestock Aren't Horny for Climate Change

If thinking about the overwhelming effects of climate change is enough to put you off your feed, then you're not alone. Across the globe, warming temperatures are affecting the appetite as well as the sex drive of cattle, pigs, chickens, and other animals. With global temperatures increasing at an alarming rate—the last decade was the hottest on record, and the temperature spiked the most in the years after 1970—animals are too hot to get hot and bothered. And that's a major problem for farmers all around the world, whose livelihood depends on the good health and friskiness of their flocks.

"It's an economic issue," explained Allison M. Chatrchyan, director of Cornell University's Institute for Climate Change and Agriculture, a research institute that helps farmers address the growing need to adapt to warmer climes. "If your cows are stressed and their reproductivity is affected, then you're definitely going to feel that in your bottom line."

In their massive 2013 report "Climate Change and Agriculture in the United States: Effects and Adaptation," authors at the USDA explain that animals affected by heat stress—a combination of metabolic abnormalities that worsen as an animal's normal core body temperature rises —causes livestock such as cows and pigs to dramatically limit all their physical activities, from grazing to playing to making sweet love, in an effort to keep their temperature down. And according to Dr. Norman Gibson, a livestock scientist based in the Caribbean, cows raised by farmers in the region also suffer from a low sperm count.

Any impact on the meat-producing capabilities of developing nations could have catastrophic effects on the countries' local economies. The USDA climate change report notes that "the livestock industry makes a significant contribution to most rural economies," and points out that meat operations can account for as much as 80 percent of the GDP in developing countries.

In wealthier nations such at the United States, farmers are trying some novel approaches to keeping their animals cool, experimenting with large-scale fans, sprinklers and air-conditioning systems to pipe artificially-cooled air into animals' barns and enclosures. But farmers in poorer countries lack the capital to invest either in such systems or in the research needed to see how effective they actually are.

"With cooling systems like those, the biggest question is: does it make sense economically?" Chatrchyan said. "Is the added cost of the energy consumption required to make a barn cool enough too high to make it worthwhile?"

Such a cost is, of course, just a drop in the bucket when considering the entirety of the meat-for-food system, which, in a vicious cycle, is in part responsible for the global warming that's making animals ill. Every year, the roughly 3.6 billion ruminants on this planet—that's cows, goats, sheep, and oxen—emit 80 million metric tons of methane, a destructive greenhouse gas that contributes disproportionately to climate change: its effect on the atmosphere is 21 times greater than CO2's. Ultimately, the effort to keep cows cool is a losing battle when those very cows are largely responsible for a changing climate.

Soon enough, more and more farmers will have to consider whether the industry they've chosen is a viable one. In addition to a drop in reproduction rates and appetite, heat stress also causes alters farm animals' metabolism and the rates at which they absorb nutrition from their food. Between eating less and failing to properly metabolize key vitamins and nutrients, farm animals are taking longer to reach their slaughtering weight, and that means a lot of lost dollars for farmers. According to the USDA report, by 2040 farm pigs will take 1.5 days longer to reach prime bacon poundage, which will cost pork producers $5 million annually. For beef, the projection is even more dire: a loss of 2.8 days to market and, therefore, $37 million annually.

And it's not just meat that livestock farmers have to worry about: heat stress also causes dramatic drops in the quality and quantity of milk produced by dairy cows.

"The worst is yet to come, and we're already seeing that dairy cows are too hot," Chatrchyan said.

Too hot, but not in the right way. If we want our cows to keep creaming, they have to stay cool.