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Beyond the Bale : Feb 07 - Mar 07 Supplement
8 BEYOND THE BALE BLOWFLY SUPPLEMENT MULESING ALTERNATIVES By Fiona Conroy Jules Dorrian, AWI's project manager for blowfly control, says a needle-less injectable mulesing substitute has been under development for a number of years and is in the process of being transferred to a commercial partner, who will complete the trial work needed to register the product with the Australian Pesticides and Veterinary Medicines Authority (APVMA). "The registration trialling process takes about 18 to 24 months and then the APVMA needs to assess the data prior to release, but this product has the potential to give effective results," Ms Dorrian says.The injectable product works by causing the treated skin to die, form a scab and then fall off. The result is similar to conventional mulesing, with the contraction of surrounding healthy skin causing stretch in the breech bare area. Trials on five flocks, involving 100 2005-drop spring lambs per property being treated with the injectable compound, are giving researchers the chance to follow the effectiveness of the treatments as the ewes grow and have lambs. The treated ewes are also running alongside conventionally mulesed ewes and ewes that have had no treatment at all. All ewes are monitored for the degree of dag and stain, flystrike incidence, fleece and skirting weights at shearing and the extent of stretch, wrinkle and bare areas around the breech. The ewes treated with the injectable product have a similar degree of stretch in the breech region as the sheep that were conventionally mulesed. Research into the potential of injectable treatments began in 2002 using a protein called collagenase, an imported protein compound derived from cattle by-products. While collagenase showed excellent results, its use was discontinued on the grounds of cost and biosecurity issues. Part of this research project also established a needle-less application method using a modified commercially available injector to administer the product, which proved highly effective. Further research by AWI identified two other active ingredients that offer potential in creating stretch in the breech region. These products have been involved in further trials, through to the stage where one compound can enter the registration process. The product developed by AWI uses cetrimide as the active ingredient. Cetrimide can be found in common antiseptics and is readily available, affordable and can be stored for up to two years. Trials into different formulations that include cetrimide have looked at the pattern of applications, operator handling issues and various concentrations. The result has been a number of formulations containing cetrimide, each with their own benefits, that the licensee can choose from. AWI research has also focused on how the product needs to be administered. "We want people to use this product consistently so we need to develop guidelines that will form the basis of training when the product is available commercially," Ms Dorrian says. "The product needs to be delivered one millimetre into the skin, which the injector does automatically at the right pressure. Our trials show the applicator needed to rest just on the skin surface for the best results. "Other trials looked at the pattern of application to ensure the best result in terms of stretch and lift without causing a loss in productivity." Research has also involved trials to determine the ideal lamb age for treatment and how treatment patterns can be adapted to different types of Merinos and still produce a consistent result. INJECTABLE SOLUTION ON THE WAY A needle-less injectable alternative to conventional mulesing is giving good results, but growers will have to wait until the product is registered before it becomes commercially available AWI is also in talks with marking cradle manufacturers about the presentation of lambs for treatment. Traditional marking cradles pull the back legs apart, stretching out the muscle and skin on the breech, potentially making the skin too thin for the applicator to work effectively. "We're working with cradle manufacturers regarding modifications to existing cradles so lambs are presented slightly differently to the operators," Ms Dorrian says. "Our research has involved looking at the practical aspect: how the product works and can be used by growers in the field to get an effective result. "The next step for the commercial partner is getting the final product registered, which involves a number of detailed pharmaceutical and on-farm trials to produce data on issues such as product safety, residues, storage requirements, packaging and any occupational health and safety issues for the operator." ú More information: Jules Dorrian, AWI project manager blowfly control, 03 9347 7161, email@example.com The result of the injector is similar to conventional mulesing (below), with the contraction of surrounding healthy skin causing stretch in the breech bare area.
Apr 07 - May 07
Feb 07 - Mar 07