WHILE the plant biotechnology sector pursues drought-resistant crops, the Sheep CRC has taken a first step towards drought-resistant sheep.
The hot, dry summers of Australia's Mediterranean climate zones produce annual "summer droughts" that are tough on livestock, and on farmers who have to supplementary feed to keep their stock in good condition.
Research by Sheep CRC post-graduate student Gus Rose is looking at whether it's possible to breed sheep that are resilient to these summer feed gaps, using the same genetic tools that sheep producers use to breed for wool or carcase characteristics.
After analysing five years of data from a research flock at Katanning, WA, Mr Rose believes that it's theoretically possible to construct a "resilience" trait based on the selection of sheep less prone to weight loss over long months of low pasture resources.
He assumes, logically, that those sheep less prone to losing weight under tougher conditions are likely to be cheaper to feed and easier to keep alive through the summer feed gap.
The next step in his research is to explore what genetic and economic consequences breeding for this trait might have on other important profit traits, like fertility or wool production.
Genetics has already identified powerful management traits, like the ability to breed for sheep less prone to flystrike or worms, Mr Rose said.
"This is just another trait that we really haven't looked at yet: working out whether you can have a sheep that you don't have to feed so much," Mr Rose said.
The impacts of such a trait could positively influence a farm's bottom line to a much greater extent than just the cost of feed.
“For example, if labour costs are included, resilience to summer weight loss might be highly valuable to farmers because it has potential to reduce labour requirements and potentially free-up more time for other enterprises, such as cropping. This allows the whole farm to operate more efficiently.”
It's going to be complicated, though. Even something as apparently simple as a resistance to losing weight when the feed dries up could affect other aspects of sheep performance.
For instance, the weight loss/gain trait that Mr Rose is working on seems to be related to fertility, a trait of very low heritability.
The key, he thinks, will lie in building indexes that will help producers achieve an appropriate balance when they work towards different breeding objectives.
Resilience will have a different value to producers in different regions.
Part of Mr Rose's project will involve surveying farmers across Australia to identify the main profit-driving traits for Merino enterprises across a range of geographic environments.
“Once we know that sheep can be genetically robust and resistant to summer weight loss during times of low feed availability, then we can start to work out the best breeding objectives to target other economically important traits in these flocks,” he said.
Another Sheep CRC student is exploring the physiology of feed intake efficiency - the physical processes that affect how sheep metabolise their feed - in a project that may eventually link up with Mr Rose's work.
Mr Rose's findings, recently presented to the annual European Federation of Animal Science (EAAP) convention, won him the prestigious prize for best scientific poster in the genetics category from a field of 100 participants.
The convention targets young scientists from the global animal science sector. Mr Rose's award earns him the right to chair a session at next year’s event.
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