Genetic tool could improve heat tolerance in cattle

Monday 18th October 2021, 4:30pm

Gene-editing methodology could contribute to climate resilience of animals living in hot climates.

Bull standing in an indoor pen - credit University of Edinburgh

Scientists have developed a gene-editing technique that could improve heat tolerance in cattle.

Their approach reproduces a naturally occurring genetic change that cattle can pass on to their offspring through natural breeding.

It was tested in a small scale study by researchers from the Centre for Tropical Livestock Genetics and Health (CTLGH) at the Roslin Institute.

This technology could be used to establish native animal populations that are better adapted to high temperatures in tropical countries, while remaining culturally acceptable to the millions of local smallholder farmers that rely on livestock for income and nutrition.

Outcomes of the work will particularly benefit cattle and farmers in tropical low- and middle-income countries, where increased temperatures associated with climate change have negative impacts on animal welfare, productivity and immunity.

Certain breeds of European cattle have reduced hair coverage compared with other breeds and so are less susceptible to heat stress – a trait caused by a natural change in a gene known as slick, named for the appearance of the animal’s coat. Researchers have developed a technique that applied an electric field to introduce genome editors designed to modify the cattle gene associated with the slick trait into newly fertilised eggs from non-slick cattle. The modified embryos were then transferred into surrogate hosts to produce healthy calves showing the slick trait. Calves were born with reduced hair coverage and showed no signs that the change in their DNA had any other impact on their health or wellbeing.

Genome editing allows researchers to introduce the changes underlying the trait directly into native breeds. Achieving this by traditional natural crossbreeding would dilute or lose traits that are desirable to local farmers.

CTLGH colleagues based at the International Livestock Research Institute (ILRI) in Nairobi will look to mirror the approach in native Kenyan cattle breeds. Heat stress is likely to become a problem in other species as global temperatures rise. Scientists will also produce and assess sheep with similar genetic modifications, as part of an EU consortium Roslin is part of, funded by Horizon 2020. 

"The world’s climate is changing and temperatures are set to increase. Establishing livestock with the appropriate genetics to improve heat resilience, particularly in tropical countries, will not only benefit animal health and welfare, but will also maximise their productivity and subsequently reduce their overall carbon footprint."

Dr Simon Lillico, CTLGH and the Roslin Institute