Cows are feeling the heat from global warming. Heat stress is one of the biggest challenges facing the beef industry, as it affects the animals’ growth and ability to reproduce.
When cattle are too hot, they tend to stop eating, which in turn threatens the longevity of the food supply coming from that herd.
It’s also the main limiting factor of production efficiency in tropical and subtropical regions, which make up about 45% of beef cattle in the world. About $369 million of beef production is lost annually due to reduced performance nationally.
“And we expect this impact to increase dramatically due to climate change,” said Raluca Mateescu, professor of animal genetics and genomics at the University of Florida.
The heat stress solution
But Mateescu and her colleagues at UF may have found a solution.
They studied the sweat glands of about 2,500 Florida cattle, primarily Brangus, which are a cross between Brahman and Angus cattle. They’re known for their ability to adapt to a wide range of environments and climates.
Cows eliminate about 85% of their body heat through sweating.
"This translates into either an ability to cool better, or not cool properly during a hot day ... that means that we can select our beef cows to maybe increase this sweat gland area,” she said.
Mateescu’s team determined that cattle can be genetically tested and bred with bigger sweat glands to better tolerate the heat, and published their findings in the Journal of Animal Science and Biotechnology.
Over the course of five years, the scientists measured the cattle’s body temperature and took skin biopsies.
They also took blood samples from these animals to analyze about 250,000 genetic markers across the genome to see which markers were associated with the sweat gland area.
“That's how we can then pinpoint which are the genes related to this variation that I see in the particular trait.” Mateescu said.
“From our research perspective… using or developing genomic tools that producers can use, that is really [an] energy efficient, sustainable approach to meet this challenge of the global climate change,” Mateescu said.
A cattle rancher's perspective
Cattle ranchers think about heat all the time, said Southwest Florida cattleman Jim Strickland, who’s been in the business for six decades and comes from a long line of cattle ranchers.
"Many of us have a lot of fans, a lot of misters in our cattle pens. We have sprinkler systems in our cattle pens. We try to work our cattle early in the morning or late evening,” he said.
Strickland said cattle are already being chosen based on physical characteristics, but those that can only be seen by eye.
So, he said incorporating genetic testing to select cattle for larger sweat glands is doable.
"That is going to be a big part of our selection criteria going into the future," he said.
Although he admits this might be an expensive endeavor as many new projects are at the start, he thinks this study’s findings will impact the cattle industry across the globe.
“This is a great study for keeping our animals more comfortable as they live in our set tropical climates around the world,” he said. “Brazil, Uruguay, Paraguay, let's just keep going, Guyana, India, Pakistan, we're talking about a lot of countries … This isn't gonna happen tomorrow, but it is going to have worldwide implications.”
