Canadian science adds to cattle genome database

Improving genetics | International collaborators sharing information

Canada plays a major role in the international effort to catalogue and share the DNA sequences of cattle, says a researcher.

A database of 234 dairy cattle genomes was recently used to identify genetic mutations that hamper dairy production. Similar collaborations are ongoing in the beef sector. A recently published paper highlighted the effort.

The work was part of the 1,000 Bulls Project in which researchers are sharing the DNA sequences of key ancestor animals from around the globe.

The results will help with genomic predictions, potentially providing a test that could identify an undesirable genetic trait in a young animal.

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Producers could then select against the trait and increase the speed of genetic herd improvements.

“If every country was having to sequence these same animals it would be extremely expensive. The cost of sequencing has come down significantly in the last five to 10 years, but it’s still an expensive thing to do,” said Mary De Pauw, project manager for the Canadian Cattle Genome Project. “It’s a wonderful opportunity.”

In the study published in Nature Genetics, 234 sequences from Holstein-Fresian, Jersey and Fleckvieh dairy cattle were used to identify mutations that lead to embryonic death and chondrodysplasia, which hinders the development of long bones, causing a form of dwarfism.

“They’ve been able to find the area in the genome where this mutation exists and so this will allow us in the future so we can do a quick test… then we can select against animals who have this mutation so that we don’t continue to breed this into our populations,” said De Pauw.

The Canadian Cattle Genome Project is focused on prolific bulls that have influenced the herds of all of the major Canadian beef breeds.

“We’ve found bulls that when you look at the number of progeny they have in our current herds, they have like over 100,000 progeny, because they were used so significantly for breeding because of their positive attributes,” she said.

“We’ve done a huge analysis of the pedigree for all of our breeds and that’s how we’ve chosen which animals to sequence.”

More than 300 animals have been sequenced because of the Canadian effort, using DNA samples that go back to 1900. In return, De Pauw said researchers can access sequences of more than 1,100 animals.

“A lot of the early data was primarily Holstein, but the beef breeds are going to be a major component of that,” she said.

Genomics is more advanced and widely employed in the dairy industry because of its focus on a single breed, Holstein, and single trait, milk production, said De Pauw.

“Genotyping is a huge thing in the dairy industry. Everybody does it and they’ve had significant gains by using it,” she said.

“But the beef breeds, because the beef industry is a little bit more segmented, it’s taken a little bit longer to get them up and going and it’s also a little bit more challenging because you’re dealing with several breeds. You’re not just dealing with one breed.”

De Pauw said genomics could also be used to select animals for carcass traits and feed efficiency.

“I think the gains will be a little bit harder in the beef industry, but we’re quite confident we can make significant strides with genomics,” she said.

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