Beef breeders look to the far north for more productive herds

Far north Queensland beef enterprises sometimes working in extreme conditions are now aided by genetic breeding methods

Russell Lethbridge of the Werrington Cattle Company
Russell Lethbridge from the Werrington Cattle Company has worked to improve his herd’s fertility traits for the past 25 years. Photo credit: MLA

The far north is the setting for technology called genomic selection and it’s being used to vastly improve fertility gains in beef cattle herds.

The research is being spearheaded by Professor Ben Hayes of the University of Queensland research institute fame who has vast experience in improving health and productivity of livestock and pasture systems.

The genomic selection technology is able to predict future offspring characteristics based on DNA data from the breeders that has been sequenced by researchers.

“The substantial impacts from the harshness of the environment for northern cattle herds and the many breeds used by the sector can be dealt with, again, provided the right data is collected,” Professor Hayes says.

“For this project, we collected data for Brahmans all the way through to Angus cattle and all crosses in between.”

Included in the project were cattle producers Russell and Donna Lethbridge who run the Werrington Cattle Co, based north of Hughenden in North Queensland.

Professor Hayes describes two key ingredients to the project’s success. The first involves the herd owners themselves who made DNA samples available through tail hairs, plus important data about the performance characteristics of their animals, including ultrasound scans obtained by vets.

Professor Ben Hayes
Professor Ben Hayes is shown here taking a DNA marker sample – hairs from the tail – off a herd in Rockhampton Qld

The second component involved an in-depth analysis of the DNA of these bulls and heifers in a process called genotyping, which is not dissimilar to ancestry DNA testing in humans.

In total there were 54 producers who assisted in collecting data from their herds.

This region was selected because it tends to experience high breeder mortality rates and low reproduction rates because of the lack of nutrition in the native pasture, recorded at levels well below what is required from grass feed.

Russell Lethbridge has worked to overcome these disadvantages by targeting fertility traits for the past 25 years, first using selective breeding and now with Professor Hayes’ breeding values.

“When they are selecting bulls, I think people are too obsessed with growth traits and don’t pay enough attention to fertility indicators such as moderate frame size, days to calving, calving ease and scrotal circumference,” he says.

“By targeting fertility, we have indirectly selected for adaptations to our environment and that allowed for a reduction in age and weight at puberty that has made a huge difference to productivity.”

With his Brahman heifers reaching puberty at 20 months, his herd is operating at 20% above the region average for reproduction levels.

This highlights the gains that are possible from the use of genome data and it shows how it can drive up fertility in cattle herds to achieve three extra calves over a cow’s lifetime, driving up both productivity and profitability.

Professor Hayes adds, “To date, we have genotyped 30,000 cattle using sets of 35,000 DNA markers that allow us to detect subtle genetic differences between animals.”

“For key bulls that have contributed important genetics to breeding programs, we upped that to 700,000 markers, resulting in more than 21 billion data points to analyse.”

Advanced computational capabilities and algorithms are used to analyse the billions of data points in myriad combinations in order to contrast animal characteristics against genomic diversity.

When it’s done well, this analysis achieves correlations between DNA marker profiles and fertility traits that are used to inform breeding strategies. “It’s a numbers game,” Professor Hayes adds.

“The larger the data, the more accurate the DNA profile tests will be to select the young bulls and heifers that produce the most fertile offspring. As the test is based on DNA, the bulls and heifers can be selected for breeding very early, potentially at birth – or even as embryos.”

Professor Hayes has now reached that stage with the fertility project. It took 54 participating herd owners pulling tail hairs to reach it, but the technology is now at the point where it is producing fertility predictions based on a DNA test, that producers can use to identify the most fecund parents.

Professor Hayes says the timing is particularly fortuitous, given that many northern cattle stations are currently rebuilding stock numbers following a run of adverse seasonal conditions.

“Part of the motivation for setting up genomic breeding for cattle herds is the opportunities to produce more beef from the same number of cows,” Professor Hayes says. “That has environmental, sustainability and profitability benefits for producers.”

Russell Lethbridge and the other 53 cattle producers were given access to the genomic selection technology project with funding from MLA Donor Company, the Department of Agriculture and Fisheries in Queensland and The University of Queensland.

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