LAMB survival has been a big focus for NSW producers Haydn and Sophie Dunhill, who are running a 3500-head flock at Rosemount, Jugiong.
The first-cross lamb operation is run alongside 400 Angus cows on 1700 hectares.
All Merinos are joined to Poll Dorset rams, with Gooramma genetics being used for the past two years.
Gooramma's work on lamb survival, particularly the selection of rams for brown fat, attracted the Dunhills to the Galong-based stud.
"We started buying there for the brown fat, as well as the good growth rates," Mr Dunhill said.
"Brown fat is what helps them survive in the first 48 hours, so we're selecting for that, because we want lambs on the ground.
"We're also looking for a moderate sized ram because they're going over Merinos, so something that will lamb easily, with smoother shoulders."
Mr Dunhill has noticed a big difference since selecting sires for brown fat.
"This year we had our best marking percentage, 120 per cent.
"Last year it was 105pc, and we haven't been able to get more than 105pc in the past."
All ewes are bought in, with Mr Dunhill focusing on a western style, plain-bodied Merino. Buying in ewes and focusing on one cross makes the lamb production a simple, but profitable enterprise which fits in with the family's cattle production.
Lambs are finished on lucerne or brassica and turned off from the age of five months, weighing between 47 and 55 kilograms liveweight, for a carcase weight of about 23kg. The Dunhills also grow oats, and improved pastures include phalaris and chicory.
"We aim for Coles, because the processor is about 10km down the road, but the heavier lambs can go to JBS at Melbourne," Mr Dunhill said.
"They're lambing on improved pasture, and we've run them in smaller management groups.
"We didn't scan for twins and singles this year, but early and late, separating them into the first three weeks and last four weeks.
"It helps with lamb marking and weaning time, and at weaning time with draft them into three groups, then weigh them from November and run them in their weight groups. That means we've got a consistent run of lambs in each group."
Brown fat is what helps them survive in the first 48 hours, so we're selecting for that, because we want lambs on the ground.
- Haydn Dunhill, Rosemount, Jugiong
Shorter gestation length, brown fat key to lamb survival
Brown fat, which is crucial for lamb survival, along with a focus on shorter gestation length, have been areas of research for Gooramma stud principal James Corcoran for many years.
He's been DNA testing sires for cold tolerance, and removing animals that are more susceptible to cold weather, for the past 15 years.
While many producers focus heavily on birthweight, it's a combination of shorter gestation and a healthy birthweight - around four to five kilograms - that makes a difference when it comes to lamb survival, Mr Corcoran said.
"We have found that when we have selected heavily for lower birthweights, it has reduced overall lamb survival," he said.
"There certainly is a sweet spot when it comes to birthweight and it isn't at either end of the extremes."
In the 2020 Bowan Park Poll Dorset progeny trial, which evaluates 16 sires from studs around the country, Gooramma 682-18 had the shortest average gestation, with 146.76 days.
"The sire of 682-18 is Gooramma Guru, who is in the top 1pc in Australia for shorter gestation length," Mr Corcoran said.
"It's fantastic to see the survival traits including gestation length flow on to the progeny."
Ruth Schwager
Ruth Schwager is a journalist with the national agricultural features team.
Ruth Schwager is a journalist with the national agricultural features team.
