Surviving Climate Change Starts With Heat-Proofing the Cow

In the hour after dawn, the cattle ranches north of Lake Okeechobee become an almost fantastical rendering of bucolic bliss. Perfect Florida sunshine rolls across miles of fire-hued grass, silhouetting idle cows in twos and threes, backlighting patches of slender, bushy-topped Sabal palms with bursts of orange and red. It’s as if a cowboy story had been illustrated by Dr. Seuss. Then the heat starts. On a typical summer day, the temperature here breaks 80F by 9 a.m., 90F by early afternoon. And it’s only getting hotter. Of the 10 warmest months on record, all but one have come since 2016. The average temperature over a 24-hour period has exceeded 88F only nine times since 1953; eight of them were in the past three years. Heat affects cattle in subtle ways, none of them good. On these ranches, a cow’s job is to give birth every year, for as many years as she can, to calves that are sent north to the corn states for fattening and slaughter. When the air gets too hot and humid, the cows’ immune systems falter, making them more vulnerable to parasites and disease. They eat less. Some wander off the grass and seek shelter in the trees, while others just lie down, stupefied. Their odds of getting pregnant fall. When cows stop becoming pregnant, they become hamburger instead. These animals are expensive to replace. It follows that as the temperature rises in this southeastern part of Florida, which has more large ranches than any other place in the country, the steaks Americans consume will get more difficult and costly to produce. So for the past three summers, genetics researcher Raluca Mateescu has climbed into a van with a gaggle of graduate students and driven to a ranch here, where they scrape, prod, pluck, and otherwise irritate hundreds of sweaty cows. A professor at the University of Florida, Mateescu is looking for a secret: how to breed heatproof cattle that still taste good. If she succeeds, she could help insulate the cattle industry from the effects of global warming, at least for a time. But the implications of her research are more sweeping than whether rib-eye has a future. In effect, Mateescu is probing the definition and scope of climate adaptation, which matters not only in the field of livestock science and agriculture but also in every other industry...MORE