Genomic tools speed genetic gain

By Sandra Taylor.

Three weeks out from weaning his hill country cows, North Canterbury farmer Andy Mason has already selected his heifer replacements.

Using genomic tools, Andy has identified the heifer calves most genetically valuable for his beef breeding operation. As long as they are phenotypically sound, they will be retained, mated as yearlings and used to breed the next generation of replacement heifers.

Fast-tracking genetic progress is typically the domain of stud breeders, but Andy is a commercial farmer with a passion for breeding top-quality livestock. He is prepared to invest in the tools to help him breed animals that will drive the future productivity and profitability of his herd.

Andy is part of the Next Generation Herds, a tranche of Beef + Lamb New Zealand’s Informing NZ Beef (INZB) programme. The seven-year INZB partnership, between B+LNZ, the Ministry for Primary Industries and the NZMeat Board aims to boost the sector’s profits by $460m during the next 25 years.

Commercial farmers contribute to genetic evaluations through the recording of data and incorporating it into breeding value predictions. This increases the accuracy with which breeding values can be estimated.

Andy and his wife Angie farm 40 hectares at Amberley House in Amberley and 1000ha of hill country in the Lowry Peaks Range near Culverden.

Their cattle operation is mainly based at Culverden where they winter 350 Angus breeding cows (mixed-age and R2s). The breeding cows are the only livestock class on the farm other than up to a dozen horses from Amberley House’s sporthorse breeding stud.

The primary objective of the Masons’ cattle operation is to breed quality beef cows that produce calves that are sought after by regular buyers at weaning.

The replacement heifer calves and about 70 of the steer calves are trucked to Amberley after weaning for growing out, and in the case of the steer calves, finishing.

Andy enjoys seeing genetics expressed in his finishing cattle. But nothing compares to seeing the productivity and profitability of his female cattle improve through genetic selection.

Sought-after calves

In the lead up to weaning in the third week of April, the cows and calves are mustered off the hills and held in 4ha of deer pens behind the yards for a few days, supplemented with hay.

This helps settle the cows and calves down before weaning and pregnancy scanning.

This year, all the cows will have tissue samples taken as part of Next Generation Herds for genomic testing and to determine the parentage of each animal. The cows are also given animal health treatments, including long-acting selenium, and about a third of the cows are drenched based on body condition.

The bulk of the steer calves and non-replacement heifers are sold directly to repeat buyers through PGG Cheviot livestock agent Nic Denton.

“Our agent Nic does a great job managing these relationships for us,” Andy says.

The replacement heifers and steers selected for finishing are trucked to Amberley.

“We haven’t sold anything at auction for four years. We have the same buyers who buy off us on the day at an agreed price per kilogram.”

The price is based on recent calf sales and the calves are truck weighed.

Along with the dries and 10-year-olds, another 10% of their in-calf cows are culled every year to allow room for the heifers coming through.

This year, structural assessor Bill Austin will go through and select the animals that don’t suit the Masons’ programme. These will be sold as pregnancy-tested in-calf cows.

Three years ago, in a bid to tighten up their calving pattern, the Masons took the bull out three weeks earlier than usual and sold the dries.

“We could afford to do this because we had a good number of heifers coming through and the effect on our average calf weight was massive,” Andy says.

Growing-out calves

At Amberley House, the 85 heifer and 70 steer calves are once again held in pens for a few days and given a 10-in-one vaccine, drench and a copper bullet. They are then rotated around pasture paddocks where they get used to moving through gateways and being handled.

In late autumn, they are run onto winter forage crops on daily shifts. Andy and Angie have been growing rape and kale, but this year have grown fodder beet as an alternative to rape to increase yield and extend feed utilisation into spring.

The yearling heifers are mated at Amberley and depending on how the spring holds out on the dryland Amberley House paddocks, may be shifted mid-mating back to Culverden.

While Andy acknowledges that this is hardly best practice, they only ever get a handful of dries in their heifers and these are sold.

“I often wonder if it’s the more nervy ones that get affected by trucking in very early pregnancy.”

Investing in yearling bulls

The bulls go out to the heifers on November 9 and the mixed-age cows on November 20.

In the past they bought the majority of their bulls from Te Mania, but in recent years Andy has sourced most of them from the Blacknight stud in Nelson’s Rai Valley. He says many of the sires the stud uses in its AI programme have strong maternal as well as growth traits and are well known in the United States and Australia.

“They have so much more data than what we can get in NZ, increasing the accuracy of what you’re actually using.”

Andy says when selecting genetics, he wants a stud quality bull at a commercial price and he particularly wants top-quality yearling bulls that can be used over the heifers to breed replacements. They are then used in the subsequent three to four years over the mixed-age cows.

He has been frustrated by the lack of quality genetics available in the yearling bull sales, as most studs will retain their best yearling bulls to be sold as two-year-olds. He has taken heed of advice offered to him by Te Mania stud’s Will Wilding who told him to think about his heifers as being his best animals and therefore the animals that should be used for breeding replacements.

“I got stuck with how to progress genetically using these heifers and found a match with Blacknight. They understood my problem and can supply me with good yearling bulls supplemented with two-year-olds bought at their public auction.”

Andy and Angie run a team of 11 or 12 bulls at mating. Seven (plus a spare if one’s available) are put to the 270 mixed-age cows which are run in one mob on steep hill country over the back of the range. Two bulls go out to 80 recently calved R3s on the warmer Culverden faces where they wintered. Two yearling bulls are put to the 85 heifers at Amberley House.

Andy says a good temperament is critical in their bulls as they cannot afford to have bulls injured through fighting, especially in the big mixed-age mob. They also don’t want bulls in remote country posing any risk to Andy or his other musterer – his very active 78-year-old father David.

The mixed-age cows, which are spread out over the hill country over calving, are consolidated into one mob around calf marking, generally a week or so either side of mating. They stay in that mob, which grows to about 650 head once the R3s and their calves are added in over the new year.

They are then rotated around the hill blocks every seven to 10 days over summer until weaning.

Selecting replacements

In the past, Andy selected his replacement heifers based on weaning weight, taking the heaviest half, but this selection method never sat well with him. He felt he could simply be selecting animals that were born early.

So, wanting to take a more scientific approach, he crunched the numbers. He worked out a $6000 investment in the genetic tool Inherit Select would quickly generate a sound return. Also, by lifting sale heifers at weaning to the average weight rather than selling the lightest half, would more than cover this cost.

“Keeping heifers based on liveweight alone is a very ham-fisted way of selecting replacements.”

As he was already taking tissue samples for Next Generation Beef, it was a matter of working with Zoetis to generate the data that would allow him to select the heifers that carried the genetics most suited to his operation.

“We’re selecting bulls based on EBVs – why not use them to select our heifers? Surely we must make faster genetic progress.”

Andy has a run a rough ruler over the cost of doing AI over his heifers as a way to speed genetic progress and believes in the first year it’s about cost neutral (not counting a time cost). However, he believes it is better to invest in quality yearling bulls that can then be used for up to four years or more.

Because they are still growing, bulls bought as yearlings tend to be more robust when grown out in commercial hill country conditions and are likely to last longer.

“They just don’t have breakdowns like some fast grown two-year-olds.”

He says there is typically very little shift in EBVs between one and two years, so he is happy to pay a premium for young animals with the right genetic and phenotypic package.

“It seems to me it’s the most appropriate way to make rapid genetic progress with a good eye on the commercial aspects.”

Other benefits

The information gathered through the tissue sampling also helps identify the bulls producing the most replacement heifer calves, as well as the most active bulls.

“At our bull-to-cow ratio of 1:40, we should be getting up to 17 heifers from each bull after allowing for dries and culling,” Andy says.

“Some bulls punch well above their weight and some just don’t get there. It’s never the ones you think are the most dominant, it just doesn’t seem to work like that.”

Because of the DNA testing, Andy is able to use bulls over a mob that could contain daughters, as he will know not to retain the heifer calves from that mating. This means they can get another few years from a good bull that they would have otherwise had to cull because of the possibility of in-breeding.

“The odds of these matings are never as high as you think they are, but we only learnt that once we had the data.”

Similarly, bulls with a good genetic package that are struggling to compete effectively against seven bulls are used over the 80 R3s where they only have to compete against one other bull.

Having seen the possibilities opened up through the use of genomic tools, Andy is wondering if one day it might be financially feasible to tissue sample the steer calves to identify the superior animals to take through for finishing.

“How much more money would it generate as against its cost? Would it be worthwhile?”

Questions that might well be answered in the not-too-distant future.

FARM FACTS

• Farm 40ha and 1000ha, North Canterbury
• Run 350 commercial Angus breeding cows
• Next Generation herd, Informing NZ Beef
• Most calves sold to repeat buyers at weaning
• A focus on speeding-up genetic gain
• Heifers are used for breeding replacements
• Invest in top-quality yearling bulls
• 10% of in-calf cows culled every year
• Genomic tool used for selecting replacement heifers.

Supplied by Beef +Lamb New Zealand.