Merinos that don’t ‘slim for summer’

Summer weight loss in sheep can be a major problem for sheep farmers in hot climates. Alan Harman looks at new research.

Scientists are a step closer to breeding Merinos that can withstand harsh summers without losing weight. These sheep could reduce feed costs and risk due to high seasonal and climate variations, and boost reproductive performance.

Gus Rose, a post-graduate student at Australia’s Co-operative Research Centre (CRC) for Sheep, conducted the research. He says reducing weight loss without expensive feed, especially in breeding ewes, would benefit livestock producers worldwide.

“It would also reduce the risks and costs of keeping sheep in good condition in summer in more marginal areas with inconsistent rainfall,” he says. “There may also be potential to run more sheep than usual in these areas.”

Rose analysed five years of data from a resource flock to discover the heritability of variations in Merino weight loss and gain. He is now investigating the links between sheep resilience to live-weight changes and production traits such as wool weight and reproductive performance.“We can then work out the best breeding objectives to target other economically important traits,” he explains.

He says including an economic analysis will let farmers plan their most profitable options. Resilience to summer weight loss might also reduce labour requirements, freeing up workers for other jobs.