Weaners and lambs are the sheep most susceptible to worms.

Their immune systems are not yet fully developed and the stress of weaning increases their susceptibility. Nutrition has a big effect on how well their immunity develops and how well they cope with worms.

The need for a weaning drench (as shown by a worm egg count) is influenced by how well the ewes have been managed for worms. If the lambing paddock was well prepared and effective worm management strategies put in place, the lambs will have little if any worm burden.

Weaners should be regularly tested for worms (worm egg count monitoring) depending on the worm history of the paddock and the seasonal conditions.

At weaning, weaners should be moved to a specially prepared, low worm risk paddock. This paddock(s) should have been prepared months in advance by utilising strategies such as 'smart grazing', cross grazing with cattle or appropriate spelling.

Creating low worm risk pastures for weaners reduces the dependence on drenching and maximises weaner weight and wool growth.