Genetic research speeds pace of dairy breeding

The genetic interval has been tightened, which means reliable breeding information is available sooner to producers

VANCOUVER — Genomic selection has revolutionized animal and plant breeding at an unexpected rate.

“Genomic selection has revolutionized animal and plant breeding around the world but I think the best is yet to come and that is through what animal scientists and veterinarians can do in terms of developing new phenotypes,” said research scientist Jennie Pryce, who is based in Australia.

Pryce is a principal research fellow with the School of Applied Systems Biology at La Trobe University and the principal research scientist in computational biology with Agriculture Victoria’s biosciences research branch.

The genetic interval has been tightened so reliable breeding information is available sooner, she said at the world conference on animal production, an international conference held every five years, which ran July 5-8 in Vancouver.

Pryce focuses on genetic improvement of functional traits in dairy cattle, optimizing breeding scheme design under genomic selection and the development of dairy selection indices.

She and her team are collaborating with scientists in nine countries from North America and Europe to better assist breeders around the world.

More information is always needed to build reference populations of live males and females. Most countries have focused on males with large numbers of offspring to provide information used to generate genomic prediction equations.

Some countries, including Australia, are starting to look at the contribution of females.

“Having females has helped us increase the reliability and we are seeing an increase in reliability of somewhere between three to five percent depending on the traits,” she said.

Working with co-operating farms, 41,000 females have been genotyped in Australia.

The majority of farmers are focused on economics and see the most value in marking traits like conformation, health and feed efficiency. Research has shown feed efficiency can vary but it appears the more efficient cows consumed two to six percent less feed to achieve the same production.

Australia also released an index of heat tolerance among cows. It appears when the temperature exceeds 20 C and 45 percent humidity, milk yield starts to drop among many cows.

More information is needed from existing animals and Pryce hypothesized that data gathered using mid-infrared spectroscopy (MIR) could be used to scale up the collection of phenotypic data.

Every time a cow’s milk is tested, a sample is sent to a laboratory to be scanned by MIR and it provides additional information. It is like a unique fingerprint for each cow.

Besides fat percentage, there is much more data available like fatty acid composition, mineral levels and other components to help assess reproduction, product quality, efficiency and health.

Research continues as more data flows in from MIR results.

“MIR and genomic selection together I think can really boost the selection that we have in traits that we were unable to think of in the past,” she said.

“The future is really quite bright in terms of the value that farmers can get from milk recording themselves. If they can get a warning in terms of whether a cow is at risk of a particular disease, that is of great value to them. It will also be extremely informative for developing breeding values for the future,” she said.

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