WITH more than 80% of sheep flocks hit by blowfly strike every year, compromising the welfare of more than 500,000 animals, producers need to take action against this disease which is at its worst from June until September-October.

Figures from Eblex show blowfly strike costs the sheep industry some £2.2m per year and as well as animal deaths there are losses from damaged wool and fleeces, plus the cost of treatment and strike control.

One of the biggest problems is treating ewes with long-lasting insecticides at the start of the season and before they are shorn, thereby much of the product is lost when sheep are sheared. Treatment of early-season lambs can also delay getting them to market.

However, basing strike control on a pour-on product such as Vectocert 1.25% provides more cost-effective protection for up to eight weeks and it has a withdrawal period for meat and offal of just eight days with no restrictions for use during pregnancy or lactation.

Rachel Clarry, of farm health company, Downland, says with so many lambs going for slaughter in six to eight weeks it doesn't make good economic sense for farmers to pay for 16 weeks' protection.

In a bid to reduce the serious impact of blowfly strike, she is urging farmers who are looking for more information on the disease to contact their relevant Downland independent distributor.

Risk of strike can be reduced by good husbandry, though, by inspecting sheep twice a day in the fly season, removing dags from early April, and shearing - which will reduce susceptibility.

She adds: "It takes constant vigilance to keep on top of the problem. Female flies can travel several miles in their search for suitable victims, and they are attracted by the smell of sweat or fleeces contaminated with decaying organic matter such as urine or faeces. But vigilance and a good treatment programme will help to reduce the industry's £2.2m annual losses."