Genomic research focuses on feed efficiency in beef sector

EDMONTON — A DNA sequence is like a script describing what an animal might become. How it actually turns out is dependent on its environment.

Sequencing of the bovine genome and subsequent research is revealing new ways to find more efficient, productive cattle. One of the more practical traits is selecting those that eat less but produce more.

Feed is a major expense so a lot of beef genomics research has been devoted to improving feed efficiency, said Graham Plastow of Livestock Gentec, based at the University of Alberta.

When scientists first started studying residual feed intake more than 10 years ago there were concerns other valuable traits might be shortchanged.

“Generally, the other traits are not affected or we have an improvement. All around it is a good story,” he said at the Alberta Beef Producers spring meeting in Edmonton.

Residual feed intake is the actual feed consumed by the animal minus the expected intake of that animal for its body size, composition and growth rate, said John Basarab of Alberta Agriculture.

“Our definition of residual feed intake is not related to body composition,” he said.

It is not correlated with growth but cattle with more feed efficiency tend to have a leaner carcass. Also, when observed at the University of Alberta’s Matthies Ranch, the most feed efficient animals seemed to seek a narrower diet of the grasses available.

“I don’t know what to make of that other than there are differences in behaviour. Efficient animals tend to be less prone to stressors and yet were a little more docile,” Basarab said.

A study from Idaho found similar results with the efficient cows grazing in different locations compared to the inefficient ones.

Other areas of genomic research are looking at crossbred cattle. DNA samples can show breed composition and parentage, which helps with crossbreeding programs to strengthen hybrid vigour.

“In crossbred cattle it is very different than making a prediction in a single breed, but we are slowly increasing the accuracy of our predictions,” Plastow said.

Research from the University of Calgary showed the odds of calves with low hybrid vigour getting sick are greater than those with more heterosis.

An international effort from Europe to develop tools to investigate more sequences and variations is being led by a project called Functional Annotation of Animal Genomes.

The $9 million project is expected to identify more of the mutations in the genome to explain variation in traits like feed efficiency.

“One of the three sets of animals to be used in the project come from Alberta,” Plastow said.

Other initiatives using genomic information include research on:

  • improving calf crop percentage
  • reducing early embryonic death due to genetic defects and out-crossing within purebreds
  • developing selection indices for commercial and purebred cattle
  • reducing greenhouse gas emissions from beef production systems to improve efficiency and sustainability
  • improving the use of new forages in a year round grazing program
  • improving disease resilience
  • reducing the use of antibiotics

Published research papers may be viewed at www.beefresearch.ca/factsheet.cfm/feed-efficiency-on-pasture-216.

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