Sheep fat storage plays role in enterprise profitability

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Murdoch University research officer Sarah Blumer and Murdoch University animal science associate professor Andrew Thompson.
Camera IconMurdoch University research officer Sarah Blumer and Murdoch University animal science associate professor Andrew Thompson. Credit: Countryman

Running sheep with more fat storage can help some farming enterprises to succeed — particularly during a tough season.

That was the message from Murdoch University animal science associate professor Andrew Thompson at the Challara Open Day on Friday in Badgingarra.

“Some 15 years ago the industry didn’t recognise the importance of fat,” he said.

“Fat provides energy reserves in the sheep’s body.

“Genetic fat can play a role in a sheep enterprise’s profitability, plus it can aid in animal welfare standards and customer satisfaction towards meat quality.”

Dr Thompson said fat was not cheap, and was four times the cost of adding protein into the sheep’s diet. “It’s expensive to put down, but cheap to keep,” he said.

“Sheep that have more fat storage, or good doers, can be run harder meaning the farmer can increase his stocking rate per hectare.”

Dr Thompson said fat played an important role in the ewe’s diet.

“In any one year, 70 to 90 per cent of food on offer is consumed by your flock’s ewes,” he said.

“Ewes that metabolise fat can draw a lot more energy from it, versus protein — as much as seven times more.”

“Recycling fat is much more efficient than recycling muscle.”

Dr Thompson said higher fat animals had a lower energy requirement. “One-half of a condition score fatter, the maintenance level is reduced by 10 per cent,” he said.

“Fatter animal have a lower based cost.

“If we have a bunch of ewes with an extra 1mm of YFat, lambs born would improve by an extra 5 per cent.”

Dr Thompson said fat that was genetically passed on to lambs would increase their survival in tougher years.

“To capitalise on fat animals, you just run more of them,” he said.

“Fatter animals have greater energy reserves or whole body energy.”

Some of the research involved in the how fat plays a role and how that trait factors in on the profitability of different sheep genotypes on a per-hectare basis, was from the Genetic Evaluation, Productivity, Efficiency and Profitability project.

Heading this up was Murdoch University researcher Sarah Blumer who undertook the first phase of the two-year project from 2019-20, with 640 wether progeny from the Merino Lifetime Productivity project based at the University of WA’s Ridgefield farm in Pingelly.

The MLP project encompasses 29 industry sires representing a range of genetics for wool, carcase and reproduction traits.

“Adult ewes with a higher proportion of whole body fat, when fed a poor quality diet, required less feed and lost less weight.” she said.

Ms Blumer said fat, as a fitness trait, improved reproduction outcomes, reduced maintenance costs and created an opportunity to increase stocking rate and/or reduce supplementary feeding.

“This poses the question of what are the genetics that will deliver an optimised lamb and wool income in a low input production enterprise, and can we develop guidelines for production systems that can be better tailored to specific genotypes.” she said.

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