DEADLY SHEEP infection blowfly strike is costing the sheep industry £2.2 million a year, according to new figures.
The financial burden of the disease, revealed by beef and sheep levy payers’ organisation Eblex, is accounted for by sheep losses, damaged wool and fleeces, plus the cost of treatment and control measures.
With the disease tending to be at its worst from June until September or October, farmers are being reminded of how best to treat sheep by farming health company Downland.
More than 80 per cent of sheep flocks are hit by blowfly strike every year – compromising the welfare of more than 500,000 animals.
Risk of strike can be reduced by good husbandry, said Rachel Clarry, Downland’s marketing co-ordinator, such as inspecting sheep twice a day in the fly season, removing matted wool from early April and shearing to reduce susceptibility.
“It takes constant vigilance to keep on top of the problem,” she said.
“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.”
A challenge for many farmers is that treating ewes with long-lasting insecticides at the start of the season means much of the product is lost when sheep are sheared, and the treatment of early-season lambs may delay getting them to market, she said.
Basing strike control on a pour-on product provides cost-effective protection for up to eight weeks, she said.
Blowfly strike is caused mainly by the maggots of greenbottle and bluebottle flies infecting sheep and lambs.
Dirty areas of fleeces are a big attraction to the flies, which is why most strikes are at the back end of animals.
Pregnant female flies can lay up to 3,000 eggs in 10 batches over three weeks.
Eggs hatch in about 12 hours and in the next three days the maggots use enzymes to digest and break through the skin. The enzymes release toxins which get into the blood stream of animals.