Milestone for merino research stock


One of Australia's leading merino research flocks is celebrating 25 years of contribution to the national sheep industry.

The Rylington Merino Flock was established in 1987 by the Department of Agriculture and Food in collaboration with a group of 95 sheep producers from Esperance to Northam.

At that time, sheep producers were starting to experience difficulties with worm control due to increased resistance to the available sheep drenches.

This flock started with 800 ewes from a wide genetic base at a Boyup Brook property called Rylington Park, from which the flock got its name.

The initial aim was to breed a flock, through genetic selection, that had natural resistance to gastro-intestinal worms.

Department senior veterinary officer John Karlsson said significant gains were achieved in just 10 years, paving the way for a new approach to sheep production.

"The Rylington Merino Flock is now also contributing to the second genetics project at the department's Mount Barker Research Station dedicated to breeding sheep with resistance to breech strike," Dr Karlsson said. "This flock demonstrated that sheep could be bred naturally that did not require mulesing or chemical control.

"We achieved this by selecting animals for breeding with a low worm egg count and low dag scores.

"One of the greatest achievements was that this genetic gain in parasite resistance was achieved without any negative impact on any other important economic traits, like wool, weight gain and fertility, whilst developing an easy-care sheep."

The flock is now based at the Mount Barker Research Station and is comprised of 500 ewes, which represent on average about eight generations of selection.

Dr Karlsson said current research was focused on breeding for breech strike resistance whilst maintaining the gains made in worm resistance. Future research was also likely to include genetic markers for some of the difficult-to-measure traits.

Research has been funded by wool growers through Australian Wool Innovation and its predecessor AWC.

"The Rylington Merino Flock has served to increase the sustainability of Western Australia's sheep flock and improve the welfare of sheep in Australian," Dr Karlsson said. "It has also received national and international recognition which has resulted in several collaborative research projects."

Sheep producers can access estimated breeding values for worm resistant sheep from the Sheep Genetics website at

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