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  • Writer's pictureFlockFinder Team

FlockFinder Guide to Drenching

When administering an anthelmintic oral drench, there are a few things you need to do in order to get it right.

Weigh – don’t guess 🤷‍♂️

  • Underestimating the weight of sheep is a common cause of under-dosing, which can allow some worms 🪱 to survive treatment and develop resistance.

  • Select and weigh the biggest sheep in the group to determine the correct dose.

  • If there is a wide range of weights, consider splitting the group and then weighing the heaviest in each section.

  • Don't forget to check that the weigh-crate is accurate before you start!

FlockFinder can help calculate the right dosage, based on the animal's weight (see screenshot above). Not only that, but it will automatically calculate the withdrawal period and update your medicine book while your out in-the-field, so you don't have to remember to do it when you get home - handy isn't it 👍!


Why not sign up today and start your 30-day free trial?



Calibrate and maintain the drench gun

  • Always check the gun is delivering the right amount before you start drenching.

  • Use a calibration pot (or remove the plunger from a 10ml syringe 💉 and hold your thumb over the end) and squirt three or four doses into it, making sure you have got rid of any air bubbles first.

  • Adjust the gun until the dose delivered is correct and re-check the accuracy of the gun at regular intervals.

  • Drenching guns should also be well maintained and replaced regularly. Clean with warm soapy water after use and check springs and tubes to make sure there are no kinks that will form air bubbles.


Drench correctly ✅

  • The drenching technique is a vital part of ensuring that the wormer does its job effectively.

  • Make sure the sheep are properly restrained and can’t leap around when you are drenching, so they swallow the whole amount.

  • Sheep can suffer serious injury, or even death, if they are unrestrained and the gun penetrates the tissues at the back of the mouth.

  • Place a hand under the head and tilt slightly to the side. Slot the nozzle in the gap between molar and incisor teeth and then over the back of the tongue.

  • You must get the nozzle over the back of the tongue. If the wormer is just put into the mouth, it will by-pass the rumen as it escapes down the oesophageal groove. This is particularly important for white (1-BZ) drenches.


Other things to consider 🧐

  • Research has shown the efficacy of the white (1-BZ) and clear (3-ML) drenches can be improved by withholding food before treatment.

  • Wormers should be stored securely, away from direct sunlight at 4-25°C. Check the use-by date and, once open, use within the time shown on the packaging. Shake white (1-BZ) products well before use.

FlockFinder also keeps track of medication expiry dates, and the amount remaining... so you don't have to!

  • Do not mix anthelmintics with any other product before administration.

  • No matter how often you use a product, always read the instructions. Recommended dose rates and withdrawal periods do change.


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