Genetic puzzle takes form

The old saying “to understand the future, we must first understand the past” rings especially true when discussing genetics in the beef cattle industry.

Research, DNA testing and genomics appear poised to leave only a vapour trail for the average cow-calf producer to grasp. Before this occurs, it’s prudent to examine the realities of what came before.

Jamie Courter, beef product manager at Neogen Genomics, says the concept of a next generation genomic profiler has been in the cattle industry for 11 years.

“We are climbing a technology adoption curve, and as we are reaching the peak, we are starting to see it trickle down into all aspects of the commercial cattle industry.”

Expected progeny differences (EPD) provided the foundation for genetics and have been a standard tool for purebred breeders since the 1980s.

With better technology, it is now possible to read thousands of DNA markers, which increases the accuracy of EPDs and potentially reveals an animal’s genetic potential. The most common genomic test available for cattle reads about 50,000 DNA markers responsible for genetic variation.

Genetic testing also determines parentage in operations that use multi-sire breeding pastures. Outliers and bulls not pulling their weight are often unavoidable, but parentage testing can identify sires responsible for inbreeding, calving difficulties, lower quality carcasses, abnormalities or lack of drive and libido. It can also point out desired qualities such as high weaning and yearling weights, premium carcasses and prolific breeders.

“There can be 10 bulls in a pasture with 250 females and we may not be able to check if they are doing their job,” said Courter.

“Once the calf crop hits the ground, what we’re able to do with genomics is take a sample on each of those calves, along with a panel on the sires and run parentage analysis.”

She says obtaining a sample is simple. Using a modified tagger, tiny plugs of flesh are taken from the ear during routine management, such as ear tagging.

Neogen Genomics has a program that creates a genetic profile of heritable traits.

Courter says it adds value to genomic testing beyond parentage identification.

“With lineage testing, you can see how cattle perform, but when you add the heritable portion for passable traits, specific females can be identified as superior for a variety of attributes such as weaning weight or calving ease.”

A single DNA sample can deliver an estimate of genetic merit for 16 economically relevant traits in replacement heifers, bulls and feedlot steers. These are summarized into maternal, performance and carcass indexes, covering traits such as stayability, weaning weight and marbling, among others.

Even modest gains in desired traits can impact the bottom line.

“Random sampling of chromosomes from closely related cattle, male or female, have shown substantial variation in genetic potential for traits,” said Courter.

“I tell people they are already doing a good job of buying the bulls that match their breeding objectives. They sire 25 to 30 calves per year but due to random biology, how do we know which heifers in that calf crop inherited the genes we want and paid our good money for? It’s easier now that we can test them.”

To demonstrate the potential gains, Neogen says a one-point increase in stayability scores would reduce the replacement rate in a 250-cow herd by 48 heifers over six years. The combined costs of those extra animals could reach nearly $100,000, plus it would take years to confirm the best heifers were actually retained.

Courter believes the most exciting advance to come to the commercial sector is an ability to proactively measure heterosis. Neogen launched a product earlier this year called Envigor, which measures the amount of heterosis as an indication of hybrid vigour.

Producers using crossbreeding methods are now able to select replacement heifers that are genetically superior in highly heritable traits. As well, they can use such programs to recognize potential in the lower heritability traits most affected by crossbreeding heterosis and hybrid vigour, such as stayability and heifer pregnancy.

Courter says many operators look to purebred breeders as genetic consultants in a way, but heritable trait testing can provide additional feedback information, data and value.

“When we understand the genetic potential in our females, we have the power to go back to the seedstock provider and say, ‘this is where I really need help. What bulls do you have that will match my need?’ Then we’re not overpaying for a bull we don’t need or missing out on one we do.”

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