Making every lamb count: Genetics for better mothers

Curiosity and innovation run in their blood, and their operation at Katanning, 320 km south-east of Perth, is certainly never the same one season to the next.

Third-generation farmer Hamish Thompson is cut from the same cloth as his father, David. Curiosity and innovation run in their blood, and their operation at Coyrecup, 320 km south-east of Perth, is certainly never the same one season to the next. Their flock is a mix of stud and commercial sheep with about 1,700 stud ewes and 2,000 commercial breeders, all run on 3,000 hectares in a mixed farming operation that also includes cropping.

Their stud first began to make waves in the mid-1990s, when David struggled to find shearers because their sheep were 'too big and too wrinkly'.

Hamish Thompson

Rather than bemoan the fact, the Thompsons made a drastic shift in breeding to shed the wrinkles, and they took no prisoners in the process. They sold half their flock that did not fit their new goals and pivoted to more cropping as they set about breeding their plain-bodied, easier care sheep.

When the next challenge arose - an industry commitment to move away from the controversial practice of mulesing - they were equally as aggressive in their decision-making. The Thompsons already had sheep that were less prone to flystrike thanks to the move away from heavy-skinned animals, and while not easy, the elimination of mulesing came as a natural progression.

In Hamish's words, 'We wanted to uncomplicate Merinos.' Ahead of their time, they were one of the first studs in Australia to offer non-mulesed Merino genetics.

One of the biggest challenges facing sheep producers is lamb survival, not just at birth but until they are weaners. The Moojepin Merino flock was fertile, but a high fetal count did not always equate to high weaning percentages. Hamish says there's too much focus on how fertile sheep are.

'We are too content as an industry to say we have fetus counts of 140-180% lambs to ewes joined, when we should be talking about the number of lambs we raise from the number of fetuses at scanning,' he says. 'The number of lambs that grow into sheep you can shear or sell to the processor is the all-important number we should be talking about.'

Lamb losses not only cost the industry in returns, but create concerns in terms of animal welfare.

Yet there is still a big gap between the number of lambs weaned to the number of fetuses at scanning. That's typical of sheep producers nationwide, and such lamb losses not only cost the industry in returns, but also create concerns in terms of animal welfare.

The increased focus on high welfare standards is coming not only from those who lobby for animal rights but also from consumers and brands pushing for livestock production methods that promote this. For Hamish, the next logical step was to find genetics that could boost lamb survival.

Some say the hard things are never easy, but that's never deterred the Thompsons. Once they challenged the accepted norm that a sizable percentage of fetuses would be lost, they set about finding ways to improve the numbers.

It's time-consuming work identifying good mothers. Even checking if a ewe has milk at lamb-marking time does not guarantee she has raised all the fetuses she was pregnant with. She could have been pregnant with triplets but may have only raised one of those.

The Thompsons saw this observational process as a means to an end, however time-consuming, and spent countless hours watching ewes mother up with lambs in the paddock and the yards. That way they could then compare the number of fetuses scanned to the number of lambs raised with that particular ewe.

Counting sheep on a grand scale has allowed the Thompsons to develop breeding values for what is known as ewe-raising ability (ERA)

Counting sheep on a grand scale has allowed the Thompsons to develop breeding values for what is known as ewe-raising ability (ERA) - in other words, picking the best mums in the flock. While this was already being picked up in a more generic breeding value known as weaning rate, Moojepin Merinos has been keen to make it a stand-alone feature they can offer clients.

'The weaning rate breeding value includes ewe-raising ability, but it also includes conception rate, litter size and the number of lambs she raises,' Hamish says.

The best thing is that these traits are highly heritable and cumulative, so the mothers keep getting better and better.

'Being fertile doesn't mean that a ewe is a good mother and can raise those lambs,' explains Hamish. He wants to show producers there is a way to breed sheep that are good mums by selecting for ewe-raising ability. 'The best thing is that these traits are highly heritable and cumulative, so the mothers keep getting better and better.'

Infusing genetics with high ERA will have flow-on effects for the flocks they go into. There will be a higher rate of conversion of fetuses to lambs at weaning, which is a bonus for farm profitability.

It's still early days, but already Hamish has recorded a lift in weaning percentages benefiting from a focus on ewe-raising ability. Interestingly, there's nothing obvious - such as temperament - about a ewe with good ERA genetics that makes her a better mum. And Hamish is perfectly comfortable with that. He sees the results at weaning, where more of the lambs that he counts as fetuses at scanning are turning up in the yards at weaning. As a strong supporter of using Australian Sheep Breeding Values for not only ewe-raising ability but also a host of other traits, things that can't be seen are par for the course for Hamish. That includes traits like intramuscular fat or marbling in meat, for example.

'There are some producers who are sceptical about how all breeding values work, let alone one for ewe-raising ability,' Hamish says.

And with the national average of about 40 per cent losses between scanning and weaning, there's certainly great ground to be made in terms of improving this.

'Ram buyers can now go out and look for sires that have high figures for ewe-raising ability if they want to lessen that loss of fetuses,' he says. 'It will help them financially and it is good for the industry.'

For the Thompson's operation, they will target losses of just 10 per cent from fetus to weaning. "It's not possible to keep every fetus, but what we are breeding for will mean we are keeping these losses as low as we possibly can,' Hamish says.

The Thompson's genetics program is also a huge plus for animal welfare, decreasing the number of lambs that die shortly after birth or in the first few weeks of life.

'These ewes bred with higher ERA will rear a higher percentage of lambs,' Hamish says. 'When you lose lambs it's like dropping $100 notes on the side of the road. 'It's more than money though. If we lose a lamb, I always wonder about the genetic potential of that sheep and wonder what could have been.'