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Australian Wool Innovation Limited
Emily King
Manager, Woolgrower Education & Capacity Building
ARTICLES >> Livestock Articles

My Strategy for Breech Modification

Posted by Bestprac on Jan 15 2009

Update from Stuart Mitchell, PAP Chairperson

In September this year, on behalf of the Bestprac network, I attended a breech blowfly strike control research update sponsored by AWI in Sydney...

This update was attended by representatives of all of AWI's extension networks, key state extension and departmental staff that will be involved in the phase out of surgical breech modification, AWI staff and some board members. Presentations were made by representatives of all of AWI's key research contractors and a number of AWI staff directly involved in the development of alternatives to mulesing.

I must apologise for taking so long to report back to you personally but my time has been very tight in the last few months.

Like most other woolgrowers attending this update, I initially sat with my arms folded expecting to hear about a "silver bullet" and refusing to believe that I would ever stop surgical breech modification.

The update was lengthy and very comprehensive and I will admit that most of us received a smack between the eyes!!

AWI's work to produce tools for woolgrowers has been outstanding. They have developed several strategies that are not stand alone alternatives but used in combination on individual properties will provide us with both short and long term alternatives to surgical breech modification.

Most of what was discussed at the update can be found on the AWI website and click on the 2010 icon or go directly to it here

To me, in a pastoral situation, the most promising long term alternative is breeding to reduce breech wrinkle and increase the natural bare area. Early results are showing that this will be moderately heritable and should not have negative correlations with other important production traits such as fleece weight and micron. My understanding is that breeding for reduced breech wrinkle has a similar heritability to breeding for lower micron, so we already have a model from the fine wool projects which does work. The only problem I can see is going finer was simplified by the use of objective technology such as OFDA and Laserscan whereas measurements for wrinkle and bareness are currently only a subjective score.

It is important that we:

• Understand how to score wrinkle and bareness. Visual sheep score guides are available from AWI Tel. 1800 070 090.
• Understand Australian Sheep Breeding Values (ASBV's) and how to use them in your flock. There is a module in the Making More From Sheep manual that covers ASBV's Data is already flowing from the CRC Nucleus Flocks to Sheep Genetics to develop ASBV's for wrinkle and bareness.
• Put some pressure on our ram suppliers to make sure they can supply ASBV's for the traits you are looking for. We recently had a very successful and practical field day in our area run by Allan Casey and Jemma Junk from NSW Dept of Primary Industries on the use of ASBV's in a commercial flock.

Clips may provide a short term solution. My simple understanding and summary of Clips is that they provide a modification about 50 percent effective as surgical modification. I wonder if a modification of this size will be adequate in a pastoral situation? I'm fairly sure it will be in my system. Clips now have a commercial partner and should be readily available next year. I have talked with other producers using Clips and they tell me that application training is essential. I also understand that it will be the responsibility of the new commercial partner to provide training. Biodegradable clips seem to be a way off and we need to consider the effect of Clips laying around our paddocks.

Progress on intradermal injection technology seems to be slow and I honestly found the outcomes a bit foggy. I don't believe that these will be an alternative in the immediate future but I am hopeful that AWI research will continue in this area as this will be a real alternative for most of us and the closest we will get to that "silver bullet".

So what's my plan?

We have made a decision here not to surgically modify our wether lambs. Dag's and breech strike in wethers is extremely rare here. We will use the TePari gas knife which stretches the skin over the end of the tail and leaves a small bare area on top of the tail. There is very little opinion about as to how good the TePari knife will work but the principle is sound. At $900 (!!) for a gas knife I hope there is some result. Jenny Treloar mentioned to me that there may be some discrimination from wether buyers against unmodified wether lambs and we must consider this but there are alternative markets for wether lambs such as meat buyers. We recently sold 10 month old unmodified wether lambs for $56 on farm and I was able to complete the wool declaration to the effect that I had not mulesed that mob. Although there doesn't seem to be a premium for wool from unmodified sheep there are plenty of threats that there will be. W! ether buyers might have to get used to unmodified sheep!?! AWI research also shows that unmodified wether lambs will have higher weights at around 10 months of age than equivalent modified lambs.

We did plan to visually score our ewe lambs at marking and not modify any score ones, use clips on the score two's and three's and surgically modify our score four's. In an ideal world we would like to cull the heavier wrinkled sheep, but low numbers in the last few years means we need to keep as many ewe lambs as we can through to classing. However, we have been unable to secure clips and training so most of our ewe lambs will be surgically modified this year. But we will work towards this system next year. We will use pain relief. I have used it previously and believe it has a really positive effect on the lambs post modification.

We chose rams last year that were plainer bodied and probably didn't rank as well as I would have liked for fleece weight however in previous years we have selected heavily for this and I'm sure a short term correction will have minimal effect. We are lucky our ram breeder is a good forward thinker and he is already working on ASBV's for wrinkle.

In summary I think there are some very positive and useful tools coming out of AWI and we just need to fit them into our own production systems. I don't think that the phase out of surgical breech modification will be as difficult as we thought. We just need to shift our paradigm's and be prepared to make changes as more tools become available.

Last changed: Feb 16 2012



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