Genomic study aims to improve breeding selection

Researchers use DNA to predict traits that affect feed efficiency, calf’s weaning weight and other factors to maximize profits

KINSELLA, Alta. — Ongoing work to select beef cattle with better feed efficiency shows that improvements are possible, but it’s slow going.

Work at the Roy Berg Kinsella Research Ranch in east-central Alberta has evaluated the genetic progress of a crossbred herd of 400 cows as well as purebred Charolais and Angus herds. Data is collected on every animal to measure im-provements throughout its life.

“We are continuing to measure efficiencies but also keep our eye on all other important traits because we want to know and understand what our selection scheme is doing to these cattle. Whether it is good or bad, we want to know,” Agriculture Canada researcher Caroline Fitzsimmons said during a recent field day at the research site, which involves researchers from the public and private sectors.

“We wanted to make a multi-trait index because we don’t advocate single trait selection at any time.… We also want to know if residual feed intake is measured in a young animal, does it translate to an older cow.”

The main herd used for research is the Kinsella composite herd, descendents of cattle owned by Roy Berg, a former dean of the University of Alberta who created synthetic beef lines by crossing Hereford, Angus and Galloways.

The replacements were selected on the basis of fertility in the females and growth in the males. Females had to calve at two years of age rather than three, and the bulls were put on a 140 day feed trial to see which gained the most.

Berg’s research was initially controversial because such crosses were not generally used decades ago. His work measured the performance of crossbreds and purebred cattle under the same selection and environment criteria. The crossbreds performed better.

The descendents of the program were eventually maintained as a special commercial research herd, and the offspring are used in the current genomic research.

Starting in 2012, DNA information was used to select for residual feed intake to align feed consumption with growth.

Cattle received their feed through the electronic Grow Safe feeding system to measure how much they ate and gained.

Two calf crops have been analyzed since 2013, which will eventually increase to five.

A small improvement of less than one percent has been noted, which is consistent with other studies of this type, said Fitzsimmons.

There is evidence that different diets, environments and stages of life can affect efficiency so cattle will be measured when they are young and when they are mature.

The plan is to eventually develop a maternal profitability index designed to maximize profit at the commercial level. This takes into consideration feed efficiency, the calf’s weight and the dam’s influence on weaning weight. The final calculation will show how much that trait contributes to profit.

Similar studies are also being conducted on the station’s Angus and Charolais herds. The idea is to select better animals at the breeding level. There are about 120 animals in each herd.

Mike Vinsky of Agriculture Canada said multiple trait selection is practiced with these two groups because commercial producers need consistency, which may be affected by single trait selection.

“When you select for one trait, then you lose out on other traits and your herd is all over the place,” he said. “Then when you take them to slaughter you are not making money, you are losing it.”

The researchers are using DNA to predict traits such as feed efficiency and other economically valuable qualities.

A DNA profile should be able to tell the producer how good the animal is or whether it has a certain trait. However, the work is slow and commonly used genomics tests look only at a small section of DNA of 50,000 markers known as SNPs.

“In the bovine genome there are 30 million markers, so we are only using what is available to us, and the accuracy is not the best,” he said.

“That is something we are working on in the next few years, to increase markers we use for selection.”

Some improvement has been found in feed efficiency but none in weaning weight in the first year. This is expected to improve slowly over time.

In addition, the Charolais herd is being ranked to create a feedlot profit index, which includes information such as hot carcass weight, saleable meat yield and marbling.

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