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Genomic technology helps choosing polled animals

By Dairy News

BREEDING NATURALLY polled animals doesn’t come at the expense of other vital health and production traits thanks to advances in genomic technology.

It’s also simple to breed hornless animals as the polled gene is a dominant trait.

The rise of genomics — DNA testing — has meant most bulls on the market have been tested for polled genes if the gene is in the pedigree.

As a result, there’s been a rapid increase in the number of polled, high Balanced Performance Index bulls on the Australian market and they are easier to identify.

In DataGene’s December 2019 Australian Breeding Value release there were 87 polled or polled carrier Holstein bulls in the Good Bulls Guide list, 10 of these were in the top 100. There were 10 Jerseys.

The uptake of polled genetics has also increased; the National Herd Improvement Association reported a 21 per cent increase in the sales of polled semen last year.

Breeding for polled is straightforward, according to DataGene’s Michelle Axford.

“The polled gene is dominant over the horn trait which means that calves that inherit the polled gene from either parent will not require disbudding,” she said.

“Genomic (DNA) testing identifies whether an animal carries zero, one or two polled genes.

Animals that have been tested are given a genetic code on DataGene’s data base.

“An animal that has no polled genes is coded POF (tested free of polled) and it will have horns. An animal that is tested true polled (POS) carries two copies of the polled gene and this animal won’t have horns. If a POS sire is used over a horned cow, all his offspring will be polled.”

But most polled bulls only carry one polled gene (POC) and about half of their progeny are horned.

To breed polled replacements, select bulls from the Good Bulls Guide with the genetic code POS or POC.

“The strategic use of polled bulls can increase the prevalence of the gene in a herd. Once the polled trait is dominant in a cow family, horned bulls can be used while maintaining the polled characteristic,” Mrs Axford said.

For more information, contact DataGene on 03 9032 7191 or enquiries@datagene.com.au or datagene.com.au