Efficacy of CLiK® Spray-On in Preventing Naturally Occuring Blowfly Strike When Applied to Unmulesed Sheep

Field studies were conducted in Australia to determine the efficacy of CLiK® Spray-On (50 g/L dicyclanil) in protecting unmulesed sheep from naturally occurring blowfly strike. Unmulesed sheep were treated on day 0 and inspected for flystrike at defined intervals thereafter. Any strikes detected were documented and resolved with a flystrike dressing. In the interest of animal welfare, untreated control groups were not maintained and blowfly pressure was determined by fly traps. Efficacy was calculated by determining the percentage cumulative strike rate at each site. In all, seven strikes were detected in 3028 CLiK-treated, unmulesed sheep. Six of these strikes were on the breech. Under conditions of moderate to high fly pressure, CLiK Spray-On protected unmulesed Merino and cross-breed sheep of various ages and wool lengths for the Australian registered protection period of 18-24 weeks, which had been previously determined using only mulesed animals. INTRODUCTION The prevention and control of blowfly strike caused by Lucilia cuprina (Wiedemann) is a vital component of sheep husbandry in Australia. Flystrike is estimated to cost the Australian sheep industry about AU$ 280 million per annum1 and it has been estimated that some three million sheep die each year as a consequence of strike.2 Mulesing is a procedure adopted as one management tool used to minimize the risk of flystrike on sheep and particularly Merinos. It involves the surgical removal of skin from around the breech of (generally) lambs to remove wrinkles and increase the area of bare perineal skin, which subsequently reduces the risk of flystrike caused by L. cuprina and other strike fly species. In recent years, the Australian sheep industry has faced strong challenges from animal rights groups on the use of the mulesing operation. These challenges have had an impact on the Australian wool industry and as a result it has been proposed that surgical mulesing should not be continued. If mulesing is abandoned, sheep farmers will need to adopt alternative practices to manage the risk of flystrike on their animals. Efficacy of CLiK® Spray-On in Preventing Naturally Occuring Blowfly Strike When Applied to Unmulesed