As cattle get too hot, they tend to stop eating, observed UF/IFAS professor Raluca Mateescu. This in turn affects their health and growth and threatens the longevity of the food supply coming from that heard.
Climate change has made it more difficult to raise cattle, so researchers are exploring ways to breed cattle that is better adapted to hotter and longer summers.
Heat stress in subtropical regions, which are the areas just north and south of the topics and generally considered the hottest in the world, is such a significant limiting factor that about $369m (£291m) of beef production is lost annually due to reduced performance nationally.
Threat to food security
“Heat stress is the main threat of food security. Under heat stress, the growth, production and reproduction of cattle are affected,” Mateescu said.
Since cows eliminate 85% of their body heat via sweat, Mateescu and her colleagues have worked to identify the genes within breeds of cattle that would lead to the sweatiest, heat-tolerant offspring.
Their study, published in the Journal of Animal Science and Biotechnology, found there is a lot of variation between cows of the same breed, in this case, Brangus – which are a cross between Brahman and Angus. Being able to select cattle to breed based on sweating ability could lead to herds that can tolerate hotter climates and still grow and reproduce.
Growing concern
“Unless we’re doing something to affect the ability of our cattle to thrive in heat stress conditions, they are not going to reproduce, so there’s a food security concern there,” Mateescu added.
The study looked at 2,401 Brangus cattle from two commercial ranches in Florida. Skin biopsies helped the researchers determine the phenotypes that contributed to the animals’ ability to manage heat stress, such as sweat-gland area, depth and length. Scientists genotyped all animals and used software to estimate genetic parameters.
The study found that a moderate amount of variation in sweating ability is genetic, so farmers could select sweatier cattle based on genetic markers. It found that genetics from both the Brahman and Angus genes positively contribute to sweating ability in Brangus cattle.