A study conducted by the University of Melbourne’s Mackinnon Project that compared the controversial practice of mulesing with the use of breech clips, and applications of a long-acting insecticide to combat breech flystrike in sheep, has found that mulesing remains the most effective method.
The three-year study, which did not include animal welfare outcomes, was led by project director, and Australian Sheep Vet Society member, John Larsen, and involved more than 6000 sheep in three self-replacing merino flocks at Nareen, Ballarat and East Gippsland, in Victoria.
Publication of the results coincided with renewed pressure by animal welfare groups on the fashion industry, urging it to ban the use of mulesed wool in the manufacture of garments, and urging farmers to ban the practice of mulesing.
Although results are still being finalised, the study has shown that clips were less effective and cost-effective as had been hoped, and provided little protection from strike during spring and early summer. Animals that were treated with the insecticide Clik however, showed a similar or lower prevalence of flystrike to mulesed sheep during the pre-Christmas peak breech-strike period.
“There was no difference in the prevalence of breech strike between the mulesed and unmulesed groups but once the protection from the chemical expired after Christmas, the unmulesed sheep were at greater risk of breech strike compared to both the clipped and mulesed ones,” Larsen said.
While no farmer enjoys the “unpleaseant” task of mulesing Larsen said it was still an effective method, although he stressed breeding for less wrinkle and wool on the breech was clearly the way forward, and where the industry “should be going aggressively”.
The study showed very little protection from breech strike was provided from clips, while unmulesed sheep took longer to crutch and suffered more accidental cuts during crutching, an animal welfare issue that Larsen said should be considered when comparisons were made with a one-off mulesing wound.
While the strategic application of a long-acting insecticide early in the blowfly season was a management strategy that producers could use to reduce blowfly populations, and prevent breech strike in both unmulesed and clipped sheep, Larsen did not recommend relying on chemicals as a control method.
He said a lack of a price-incentive for unmulesed wool had resulted in anecdotal evidence some producers were reverting to mulesing, because both practically and economically it was: “just so damn effective”.
Anne Layton-Bennett