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Beyond the Bale : Jun - Jul 08 Supplement
on-fArm CAse study frame, fine wool and long staple length, the bonus of a semi-bare breech. These genes for cleaner, less woolly backsides, are already showing through strongly in its progeny. “So I think the genetics for bare breech are very heritable, although it’s not what I would suggest you should select for as a first priority,” he says. “I think you have to stick with selecting for your main criteria of frame size, wool type, fleece weight and staple, but then use bare breech as a secondary factor along with something like worm tolerance.” Dealing with reducing the natural incidence of flystrike through sheep selection is an ongoing process at ‘Murrayfield’. Mr Michael believes that standard genetic variation within any flock will result in some sheep that get heavy infestations of worms, but do not end up scouring, and others that may not get hit so hard but scour badly. Similarly, he thinks that while the fly threat may be similar for all the flock, some sheep will be badly affected by flystrike, harming health and wool quality, while others will escape. Already ‘Murrayfield’ is selecting for this natural genetic variation. Ewes at shearing whose fleeces show evidence of breech flystrike are In 005, Bruce Michael (left) did not mules any of the 500 lambs on ‘Murrayfield’, Bruny Island, tasmania. A steep learning curve followed, but no regrets. PhotoS: Sue neALeS instantly culled. So too, during the year, are ewes that are badly scouring when the rest of the flock appears relatively unaffected. His aim is not to breed some super Merino line that is worm resistant and flystrike resistant, but sheep that are bare-breeched, and worm and fly tolerant. “And I’ve been really surprised that some of our younger sheep – not enough yet – are already showing signs they are naturally reasonably bare-breeched.” Management practices have changed to adjust to the property’s no-mulesing ethos. At weaning, all young sheep are sprayed with Extinosad® anti-flystrike chemical to get them through to their first crutching in February. After crutching, Mr Michael has decided it will still be necessary to put two clips on the base of each weaner’s tail to remove extra skin and to prevent tail dag build-up; he does not think breeding pressure will change the tail issue. But breeding and management have made the need for any breech clips redundant at ‘Murrayfield’. The continuing need for tail clips is an extra cost imposition, since the weaners have to be brought back in to the yards two weeks later for the tail clips to be removed. Over time, Mr Michael hopes these tail clips will become both cheaper and biodegradable, removing the need for a second muster. The big difference in management practices, he says, is the need to monitor the flock, especially the weaners, much more regularly, to watch for early signs of scouring and dags indicating worm problems. Fecal egg count (FEC) worm testing is conducted on mobs. “The management of dags right through the flock is going to be our key tool now, because if you don’t have dags and can control scouring, no matter how much wool is on them, you won’t get flies. “We are also going to investigate the use of fly traps to reduce the number of flies and eggs around. We just have to be much more switched on these days.” But the marketing benefits of non-mulesing are already clear. All wool from ‘Murrayfield’ is now classified as non-mulesed and chemical-free, and qualifies for prized chain-of-custody and organic certificates. This enables the entire clip to be sold directly to the NewMerino group at a three per cent premium on standard wool prices, where it is on-sold to eco-friendly clothing companies and textile manufacturers. This, in turn, adds another cost saving for ‘Murrayfield’ in that its wool clip does not need to be classed into multiple lines at shearing but is sold as one line with stained fleece parts removed. “I don’t think not mulesing has made us a lot of money, but it hasn’t cost us anything either,” Mr Michael says. “And soon you just won’t be able to sell your wool if you still mules, or it will be sold at such heavily discounted prices it wouldn’t be worthwhile.” Mr Michael makes no claims to have got everything right at ‘Murrayfield’ since abolishing mulesing. He and his staff are still learning and adjusting their practices as the dual impacts of changed breeding selection strategies and new management pressures become apparent. He has not ruled out even more radical shifts in the future to prevent the incidence of flystrike, perhaps shearing three times every two years or crutching twice a year. But Mr Michael has no regrets about the property’s 2005 decision to stop mulesing. “The whole thing is constantly evolving and we’ve still got a long way to go before we will put up our hands and say we are experts at running a non-mulesed flock. But the challenge to build the flock structure and management system around non-mulesing is very exciting. “And frankly, I don’t think you can be in the Merino wool industry these days without having these responsibilities for animal health and wellbeing.” ú roAd to 010 SuPPLeMent Beyond the BALe 5
Apr - May 08
Jun - July 08