On John’s farm there is always much discussion about rotating, and minimizing, the use of worm drenches. The trouble is the ewes really go downhill if they start scouring as with the back paddocks it...

On John’s farm there is always much discussion about rotating, and minimizing, the use of worm drenches. The trouble is the ewes really go downhill if they start scouring as with the back paddocks it is some time before the situation becomes clear. Thus, should a regular drench regime be continued or should an ‘on-demand’ system be instituted? The benefits and costs of getting it right are significant, but the situation is so variable from year to year.