The Sustainable Management of Parasites in Sheep (SCOPS) group is encouraging sheep farmers to watch ewe physique situation scores to cut back the doses of wormer the administer this lambing season.
The group has mentioned that new proof helps this method as a strategy to lower the proportion of ewes wormed round lambing time, with out detrimental results on lamb efficiency.
Talking on behalf of SCOPS, impartial sheep guide Lesley Stubbings mentioned the stress of late being pregnant may cause a ewe’s immune system to wane and permit grownup worms in her intestine to supply extra eggs.
“This is named the peri-parturient rise and the worm eggs, handed out within the ewe’s dung, contaminate the pasture grazed by their lambs later within the season,” he mentioned.
“The target of utilizing a wormer at lambing time is to cut back the extent of pasture contamination and the next problem to lambs. It usually has nothing to do with the well being of the ewe.”
SCOPS warned that worming all ewes at lambing time within the hope of decreasing the danger to their offspring is high-risk when it comes to accelerating the event of resistance to wormers on a farm.
Lowering the proportion of ewes wormed reduces this danger, SCOPS mentioned, and helps gradual the event of resistance.
“For some years, SCOPS has really useful at the least one in 10 of the fittest ewes are left untreated to cut back the choice for resistance within the worm inhabitants,” Stubbings mentioned.
“Nonetheless, as resistance ranges improve, we have to higher establish these ewes more likely to produce the best degree of contamination and when this if more likely to happen, so remedy will be timed extra precisely.”
SCOPS mentioned it has been watching a analysis venture in Wales that has proven a major variation within the extent, timing and period of the peri-parturient rise, each between particular person ewes and between farms.
“This newest analysis suggests, slightly than simply leaving the fittest or single rearing ewes untreated, you should utilize lack of physique situation in your ewes to establish these below probably the most dietary stress and subsequently extra more likely to produce a excessive variety of worm eggs of their dung,” Stubbings mentioned.
“In most flocks this implies the proportion handled will be diminished. That is important to handle considerations over the blanket use of long-acting moxidectin 2% wormers in ewes.
Stubbings mentioned that whereas these merchandise scale back egg output over an prolonged interval, and subsequently can scale back pasture contamination, in addition they imply the worm inhabitants is uncovered to the lively for longer.
“Taking this new method means we will goal solely these ewes more likely to produce probably the most contamination, harnessing the potential of moxidectin whereas making certain minimal choice strain is exerted,” he mentioned.