Reports of overdosing have happened on some sheep farms across the UK in recent months, industry body SCOPS says
Sheep farmers are being urged to take care when using wormers and flukicides containing the active ingredient closantel following reports of overdosing.
Giving an animal too much closantel can cause permanent blindness, the Sustainable Control of Parasites in Sheep (SCOPS) has warned.
Reports of overdosing have happened on some sheep farms across the UK in recent months, according to the animal health body.
Closantel, an important active in the control of internal parasites, is contained in Supaverm and Flukiver, Solantel, Closamectin and Closiver.
Speaking on behalf of SCOPS, independent sheep adviser Lesley Stubbings says animals should be dosed with closantel according to their weight.
“The safe use of animal medicines relies on all the instructions for use being followed as per the label – and we know a key issue is ensuring animals receive the correct dose."
Current industry advice is to dose with a wormer or flukicide to the heaviest in the group – advice that needs to be followed carefully given the closantel risk.
Ms Stubbings continues: “Because of the risks posed by overdosing, SCOPS urges sheep farmers to split a group if the weight variation is large, grouping sheep into weight bands and altering the dose rate accordingly.
"That is safer than dosing to the heaviest animal and administering too much closantel to small animals.”
SCOPS also encourages sheep producers to report any adverse reaction to closantel in treated animals to the Veterinary Medicines Directorate.
There is a full list of products that can used to treat internal sheep parasites on the SCOPS website, which highlights the active for each.
The website also provides links to the VMD product database and adverse reactions reporting process.
Ms Stubbings concludes: “This isn’t a recommendation to avoid the product – just a reminder of the risks of not weighing animals and giving them too much.”