These drenches generally have a good activity against adults, in some cases approaching 100 per cent. On the other hand, efficiency against immature worms is extremely variable. But it must be recognised that it may take only five or ten worms to kill a horse in certain circumstances. Daily egg production from some worms can be measured in thousands per worm, so it can be appreciated that we place a heavy reliance on drenching to protect our horses. Administration Paste drenches Pastes are extremely convenient and easy to use.
Dosage is easy to adjust, and pastes are well suited to be part of a regular drench program.
Always ensure the horse's mouth is empty of food, and deposit the drench as far back in the mouth as possible. Some powder and liquid drenches are sufficiently palatable to be accepted when mixed with feed. Liquid drenches are preferably administered into the mouth using a hook, pump or syringe. One problem with oral administration of liquids is that of frequent loss of drench. Granules and pellets Other drenches have been specifically formulated for mixing in the feed and are presented as granules or pellets.