Bull breeders ‘zeroing-in’ on horn status in selection

Jon Condon, 26/08/2014

THE industry-wide drive for labour efficiency, better animal welfare outcomes, reduced bruising and the constant challenge of workplace health and safety suggests breeding polled cattle is a no-brainer for those who can achieve it.

And with advances in the accuracy of the poll gene marker test since its original launch in 2010, more seedstock producers are tackling the challenge with greater intent.

Bull breeders attuned to the value of breeding more polled cattle are starting to make rapid progress in shifting their herds’ horn status, based on improved DNA testing capability and a general ‘shift in priorities’ among commercial bull clients.

This sentiment was in clear evidence at a recent beef field day held at Yulgilbar Station on the Clarence River in northern NSW.

Yulgilbar manager Rob Sinnamon runs the biggest registered Santa herd in NSW, and he said the stud’s ultimate aim, over time, was to move to 100 percent polled status.

Industry consultant Bill Hoffman gave a presentation at the field day on utilising technologies to make economic gains in the beef industry and identifying homozygous poll sires to capitalise on the poll factor.

On this occasion, Mr Hoffman was presenting on behalf of MLA, which was one of the collaborators in the research that delivered the industry’s poll gene marker test in 2010, since upgraded and refined.

Mr Hoffman provided a summary of phenotype (what you see in an animal, i.e. his coat colour, appearance of horns etc) and genotype (the animal’s actual genetic makeup) using a couple of human volunteers holding cards showing different combinations of the two possible alleles (markers in the genes)  for horn status, and the distinctions between homozygous and heterozygous polls.


Click here to learn more about the differences between homozygous and heterozygous polled cattle, and how their progeny are likely to throw, horn status-wise.

The poll gene test was first released in 2010 by the CRC for Beef Genetic Technologies, but has since been refined with increased accuracy and application across a wider number of breeds.

“I’m not here to tell you that you must aim to breed polled cattle, but its pretty obvious that nobody likes dehorning calves,” Mr Hoffman said.

“If you want to reduce the number of calves you have to dehorn, breeding polled cattle is one option. And importantly, the selection of the (homozygous) polled bull will assist you greatly in maximising the number of calves you don’t have to dehorn,” he said.

“But it’s not a fix-all in one generation. You don’t go out and buy a PP bull and wipe out horns in a single cycle. In this case, there is still going to be a lingering group of progeny with horned genes in there, and if you use a PH bull, the path will be even longer to work over those horned genes in the herd.”

Mr Hoffman said the test, which simply required pulling a tail hair as a sample, was applicable across a wide number of breeds.

“But it’s important to point out that the test is not totally definitive – there is still the possibility that you will get a ‘non-informed’ result on some bulls, and each breed carries its own test accuracy figure.”

Among popular breeds, these range from 97pc accuracy in the case of Brangus and 96pc for Hereford, to 82pc for Droughtmasters, 86pc for Charolais and 89pc for Brahmans. Other breeds are intermediate.

Asked how the test responded to the presence of scurrs, Mr Hoffman said it still lingered as an issue in the whole prediction equation, especially for Bos Indicus cattle.

“That’s because we’re still not testing the gene itself – we’re testing for markers. But the positive aspect in the latest version of the test is that the accuracy has moved upwards enormously, in predicting the true polled outcome,” he said. “For most breeds, it’s up around 90pc.”

“Certainly the test offers a major step towards minimising the number of horns that a beef producer needs to remove, if they want to go that way.”

Asked whether there was value in testing stud females as well as bulls, he said he wasn’t aware of stud females yet being tested, but there was potential in doing so to establish an elite PP female herd within a stud.

“It could already very well be happening, among those breeders who want to get there faster,” he said.


What should a homozygous poll bull be worth?

Beef Central asked Mr Hoffman what a homozygous bull should be worth over a PH or HH bull, all other traits being equal.

Beef consultant, Bill Hoffman, speaking at the Yulgilbar field day

Beef consultant Bill Hoffman speaking at the Yulgilbar field day

“Each seedstock and commercial bull buyer is going to value him differently,” was his reply.

“For a commercial producer who is starting to think about the collective value of not having to dehorn cattle, and perhaps has an ongoing aim of heading towards a polled herd in future, it could be worth quite a lot.”

“This test gives the producer the opportunity to speed-up that process, once the decision has been made – much faster than simply buying phenotypically polled bulls (could be either PP or PH), and hoping for the best.”

While it was still too early to see evidence of more polled seedstock cattle in breed-wide analysis, within some individual studs, the process was now gaining momentum.

“Yulgilbar, for example, has already made huge steps towards the objective. That’s in clear evidence not only in this year’s sale catalogue, but also in even greater numbers in next year’s calves and the year after that.”

“This is the first year that the Yulgilbar catalogue has a significantly larger number of polls than what would be seen in the normal population of Santas. Value-wise, let’s come back after the sale on September 5, and see what the buyers think,” Mr Hoffman said.


Yulgilbar’s solid selection progress

This will be the second year that Yulgilbar has offered poll gene test status on bulls in its spring sale catalogue. In this year’s lineup, bulls marked with a (P) after their name (phenotypically polled) will all have been tested, with their genotype identified as PP or PH.

Yulgilbar's Rob Sinnamon

Yulgilbar’s Rob Sinnamon

“Back when we started this process (in 2002, pre-dating the launch of the DNA test, but based on visual assessment) we only had about 12pc polls in our herd,” Yulgilbar manager Rob Sinnamon said.

“Now we’re about 60pc phenotypically polled, but of that 60pc, probably only 20pc are homozygous PP polls,” he said.

“It’s been slow, but steady process, but as we can use the testing tool now, we’re able to speed that process up. Ultimately, our aim is to achieve a pure poll (PP) herd, and we want to be ahead of the curve in achieving that.”

The challenge was in increasing the number of cattle that are PP for horn status, which also have the desirable performance, growth and other traits stud breeders are looking for.

“If we see a sire that has all the other traits we want, we can test him and if he proves to be PP, it’s a bonus,” Mr Sinnamon said.

That proved to be the case with Yulgilbar’s earlier elite headline sire purchase, Warenda Sahara, for which the stud paid an Australian record of $80,000. He was only DNA tested after the sale, and proved to be a PP animal, which proved an ‘absolute bonus.’

“He’s produced 600 or 700 calves now through AI, and we haven’t seen a horned calf,” Mr Sinnamon said.

At last year’s Yulgilbar sale, there was a $2300 price premium paid for poll bulls over horned, and there were a couple of buyers who attended specifically to buy homozygous polls.

“They’d embraced the technology and want to turn their herds quickly towards polled. Craig Ross from Nebo, Central Queensland was one, and he paid an average of about $7500, so they are already attracting a premium.”

“Obviously with issues the livestock industry has seen in recent times in areas like mulesing suggests we could see similar challenges arise in areas like management of horned cattle in the future,” Mr Sinnamon said.

Since 2007, Yulgilbar has focussed on purchasing only polled Santa genetics, and it was only after the DNA test became available in 2010 that the stud could start to identify those homozygous (PP) polled cattle with any certainty.

“We’re passionate about breeding polled cattle now – we’re using the test as another tool, so long as we are not foregoing any of the other criteria in performance, weightgain, growth and other traits, that we see as important in the economic production of beef.”

Mr Sinnamon said 15 or 20 years ago, he would have agreed with some of the ‘old acorns’ about the lack of bone in polled cattle.

“But I think if you look in the Santa Gertrudis breed particularly, a lot of the better genetics and good Breedplan performance are in polled cattle,” he said.


Pesti test now a ‘given’

In other data identified in the Yulgilbar sale catalogue, the business tests every sale animal for pestivirus PI freedom – a policy it has followed for the past four years since the PI test came out.

“We’ve been heavy-users of Pestigard since the vaccine came on the market, and since the PI test came out, we’ve been fortunate in that we have not recorded one positive PI result in the herd,” Mr Sinnamon said.

“It means we have to maintain a high level of biosecurity on the property, but we see it as an important value-add for our bull buyers. As producers increasingly become aware of pesti and the damage it can do, it is becoming a valuable feature in our offer to clients.”

“I don’t think we’re necessarily getting a price premium for it, but it’s a customer service issue, giving them watertight confidence that we’re not going to sell them a product that is going to produce a fertility crash in their herd.”


  • Click here to access information about the Zoetis (Pfizer) HornPoll DNA test.




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