How to make the most of your drench

How to make the most of your drench
By Ashley O’Driscoll, Veterinarian, Anexa Vets Ngaruawahia

Nothing in life is free, and deworming drenches are no exception. So why throw your money away? This article is aimed at dairy calves, but the concepts can be applied to any animal getting drench.

I know it sounds simple, but first off - get the dose right! Before you drench, weigh a sample of calves to ensure that you are giving the correct dose. Set your dose gun for 10 kg above the weight of the heaviest calf. If the weight range is large, you may have to split the calves into two separate dose groups based on weight (to avoid giving the light calves an overdose). Do not under-dose your calves!

Before you proceed with drenching, put aside 10 minutes to check your equipment. First, check that your gun and tubing are not sucking up air or leaking drench. It is very hard to get the dose right otherwise. Secondly, fill your drench gun to a set dose (for example, 20 mL), and squirt this dose into a syringe. If the dose on the gun does not match the amount of product in the syringe, either adjust the gun or get a new gun!


For oral drenches, make sure you get the gun up and over the base of the tongue. The dose will not be correct if they spit a significant amount of drench out. And they do try to spit it out because oral drenches taste horrible.

For pour-on drenches, make sure that the drench is spread in a line evenly along the back, from the shoulder blades to the pelvis. This is how drench studies apply drench- there is no guarantee that a drench will work if it is all poured on one spot on the animal.

Do you calves need drenching?

Just because they are scouring it may not be worms! Do a drench check.

If you have any questions about drench, don’t hesitate to contact your local Anexa clinic.

Date Added: Wednesday, 31st March 2021