Sheep Worm Control Strategies
Drenching is the most common and relatively easy method of dosing sheep but injectables are becoming more popular and can give multi purpose cover for ectoparasites e.g. Scab mite as well as in the case of Cydectin LA give prolonged worm cover.
The strategies below are worth following if possible to reduce the on farm worm burden and thereby the reliance on anthelmintics.
This is the ideal form of worm control, if you have the ground available, and is essentially aimed at minimising infection. It involves low stocking densities and turning out lambs onto pasture not grazed by lambs in the previous year until May. This method prevents the build up of heavy contamination on pasture and avoids exposure of lambs to infective Nematodirus battus larvae.
Many sheep now carry worms that are resistant to the various anthelmintics drugs and it is important not to bring these worms onto your holding. The simplest way to do this is to run a closed flock and breed all replacements from home.
All sheep that are bought in should undergo a quarantine period on arrival. They should be drenched with a levamisole based product (yellow drench) and also given an avermectin based product (clear drench or injectable such as Cydectin or Dectomax). The latter will also treat for sheep scab. Following a 24-48 hour quarantine period, all of the susceptible worms should have been passed, the sheep should then be grazed on pasture recently used by the current flock so that they pick up the resident worms on the holding.