Sweaty cows may not seem like the most interesting animals, but in a warming world, researchers are obsessed with them.
“Cows tend to stop eating when it’s too hot, which affects their health and growth and threatens the longevity of the food supply from the herd,” said Raluca Matieescu, professor in the Department of Animal Sciences at the University of Florida’s Institute of Food and Agricultural Sciences (UF/IFAS).
Climate change is making raising cattle more difficult. Growth and reproduction are affected by heat, so it’s important to breed cattle that are adapted to hotter, longer summers. Cows lose about 85 percent of their body heat through sweating, she said.
Heat stress in the subtropical region just north and south of Topic, generally considered the hottest in the world, is a huge limiting factor, she said, with lower productivity nationwide reducing beef production by about $369 million per year.
“Heat stress is the biggest threat to food security. Under heat stress, cattle growth, production and reproduction are affected,” Matiesk said.
A new study published in the Journal of Animal Science and Biotechnology by Matiesk and his colleagues found that it’s possible to identify genes within cattle breeds that produce the sweatiest, most heat-tolerant offspring.
He said the study found that there are many differences even among the same breed of cattle — in this case Brangus, a cross between Brahman and Angus — and that being able to select cattle for breeding based on their sweating ability could lead to herds that can tolerate, grow and thrive in hotter climates.
“There are food security concerns because unless measures are taken that affect the ability of cattle to reproduce under heat stress, the cattle will not reproduce,” she said.
The study involved 2,401 Brangus cattle on two commercial ranches in Florida. Researchers used skin biopsies to identify phenotypes that contribute to an animal’s ability to manage heat stress, such as sweat gland area, depth and length. Scientists genotyped all the animals and used software to estimate genetic parameters.
The study found that moderate variation in sweating ability is genetic, allowing farmers to select cattle that are more likely to sweat based on genetic markers. Both Brahman and Angus genes were found to have a positive effect on the sweating ability of Brangus cattle.
