Crossbreeding cattle for heat resistance

SEAN BRADY STAFF REPORTER sbrady@kamloopsthisweek.com

Thompson Rivers University researcher John Church says he’s very encouraged by early results in his attempt to make B.C. cattle more heat resistant.

As cattle research chair at TRU, Church is working with three ranches near Kamloops, including Sun Peaks, Barnhartvale and Kelowna.

Church has worked with forward-thinking ranchers to crossbreed Red Angus cattle with Senepol cattle, a breed found in the Caribbean.

“The Senepol has developed this unique mutation, called the slick mutation, which means their summer hair coat is a lot thinner,” Church told KTW.

Along with the thinner summer coat, Church said the cattle may also have an enhanced ability to sweat and tests are also being done to look for internal metabolic changes that would also allow for more heat tolerance.

Church cited extreme weather and ever-increasing temperatures due to climate change as the reason for the study.

“I decided to investigate this because the impact from these heat domes is just unbelievable,” Church said.

Cattle aren’t dropping dead en masse in B.C. due to the heat just yet, but Church said he did hear about heat-related cattle deaths in the Lower Mainland, mostly among dairy cattle, but also among beef, which is the type Church is working with for the project.

In June 2022, heat stress was blamed for the deaths of thousands of cattle over just a few days at feed lots in Kansas. Church said because B.C. exports the majority of its calves, the extra resilience could be spread elsewhere.

“I think this might be the future. We used to think that we needed a lot of high humidity to be lethal and we know that’s not true anymore,” Church said.

While cattle can generally tolerate high daytime temperatures, it is sustained high overnight temperatures that can cause mortality.

“Cows don’t dissipate heat, even as well as people do. It’s more that they need a chance to cool down at night,” Church said.

While the Senepol breed originates in the Caribbean, the provenance of these B.C. cattle is a little closer to home.

Church worked with a company in Alberta, which had frozen Senepol embryos in storage. They had been there for 18 years, frozen in tanks of liquid nitrogen.

Working with Paul Adams of Kwantlen Polytechnic University, Church said that university has done work in sequencing the genomes of the offspring produced using the embryos.

That’s something that wasn’t even possible back when the embryos were frozen, Church said.

Church said the foundation stock is three-quarters Senepol and one-quarter Angus, which is then bred back to what Church calls a Sen-Angus — threeeighths Senepol and five-eighths Angus.

But he’s not stopping there. He said there are also plans to cross with Black Angus breeds, as well as other breeds that grow double coats in the winter, making them more resilient to both extremes.

“You need an animal in Canada that is capable of handling, probably plus-50 C on the hot side, yet can still handle -40 C in the winter. It’s an 80- or

90-degree temperature swing,” he said.

Initially, there were concerns over how short-haired animals would fare in the winter, but Church said so far, so good.

“That was probably the thing people were most concerned about, if they’d freeze to death in the winter. We haven’t seen that at all. They seem to do just fine,” he said.

Church expects a heatresistant crossbreed to be ready in five years but said the market for the breed will be determined by how quickly climate change occurs.

“I think we can have something in five years. If we waited until 2030, that’s too late to start changing,” he said.