Productivity & Flystrike Resistance
Merino Breeders wishing to boost sheep productivity and reduce susceptibility to blowfly strike can gain powerful new knowledge from the newly published Merino Superior Sires 14 report.
Executive officer of publisher Australian Merino Sire Evaluation Association, Ben Swain, says the report, produced annually since 1994, enables breeders to compare hundreds of top sires evaluated at up to 14 sites across all the major wool growing regions.
"We have data on all commercially important, measured traits and up to 19 visual traits going back nearly 20 years," Ben says.
"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 the Merino Superior Sires report 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 and satisfy retail demand for wool from unmulesed sheep.
Recent research funded by AWI has confirmed that rapid change towards plainer sheep with significantly reduced wrinkle and breech cover is achievable and many growers are now actively pursuing this strategy.
Ben Swain, who is also a commercial woolgrower at Gunnedah, says many growers remain concerned that breeding and selecting for lower wrinkle and crutch cover will 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, while fairly negative, is not strong enough to prevent us from selecting for decreased fibre diameter and increased fleece weight," Ben Swain says.
"All the indications are that the correlation between wrinkle and fleece weight is less negative 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 should increase financial returns in the future, it may slow your progress in existing traits and it certainly won't send you off track chasing fads."
Ben says that genetic change takes time and he urges breeders to move on pursuing change today.
Merino Superior Sires has traditionally been published in February but the latest edition has been brought forward to provide a timelier source of independent information for breeders selecting sires for the 2009 joining season.