Selecting rams with a genetic history of bare breech in order to counter flystrike, need not come at the expense of other productive traits, according to the Australian Merino Sire Evaluation Association.
It has just published this year's Merino Superior Sires report, which includes details of performance indicators including traits like breech cover.
Executive officer of publisher Australian Merino Sire Evaluation Association, Ben Swain, said the report enables breeders to compare hundreds of top sires evaluated at up to 14 sire evaluation sites across all the major wool growing regions in Australia.
"We have data on all the commercially important measured traits and up to 19 visual traits going back nearly 20 years," Mr Swain said.
"This is a very valuable resource for Merino breeders. It allows them to match sire selection to their specific breeding objectives.
"The visually evaluated traits include body wrinkle, breech wrinkle, breech cover and crutch cover.
"Using Merino Superior Sires and the more detailed individual site reports available at www.merinosuperiorsires.com.au, breeders can select for plainer, lower wrinkle sheep as well as for higher productivity."
Breeding and selecting plainer sheep with reduced wrinkle and crutch cover is a key component of the wool industry's drive to phase out mulesing.
Recent research funded by Australian Wool Innovation has confirmed that rapid change towards plainer sheep with significantly reduced wrinkle and breech cover is achievable, with many growers already actively pursuing this strategy.
But Mr Swain said many growers remain concerned that breeding and selecting for lower wrinkle and crutch cover would simultaneously select for lower productivity.
"We now know from data accumulated through Merino Superior Sires and from other sources, that the correlation between fibre diameter and fleece weight, whilst negative, is not strong enough to prevent us from successfully selecting for decreased fibre diameter and increased fleece weight," he said.
"All the indications are that the correlation between wrinkle and fleece weight is less negative than that between fibre diameter and fleece weight, which means faster gains can be made in the right direction on both traits.
"Breeders can add reducing the incidence of flystrike to their current breeding objectives when using Merino Superior Sires to identify suitable sires.
"For example, you can select for productivity traits such as fleece weight, fibre diameter and staple strength at the same time as reduced wrinkle.
"This will get even easier with current moves to develop across flock Australian Sheep Breeding Values (ASBVs) for visual traits, as well as measured traits.
"Adding another trait to your breeding objective may slow progress in existing traits, however it certainly won’t send you off track chasing fads and should increase financial returns in the future."
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