Before and during drenching, guns must be both pressure checked and calibrated.

• To pressure check a drench gun, fill the barrel fully with drench, seal the nozzle with a finger or thumb and attempt to depress plunger. It should not move. If the plunger depresses, drench is escaping back past the seals.
• Calibrate the volume by setting the gun volume to, say, 10mL and deliver 10 squirts of drench, not water, into an accurate measuring container. Have the gun serviced if there is a problem with pressure or calibration.
• Oral drenching technique: gently place the gun over the “back” of the tongue and depress gently.
• FOLLOW the label carefully for all products.
• Do not mix unproven trace elements or rumen modifiers with drenches as this may affect the efficacy of the drench, the additive or both.

Avoid under-dosing
By ensuring the dose volume is based on the heaviest animal in the mob. If there is a wide amount of variation in body weight, split into smaller mobs and dose to the heaviest within these sub groups.

How much drench do you need?...

Yarding
Prolonged yarding of stock prior to drenching cannot be fully endorsed, even though this practice has been shown to slightly increase the efficacy of oral BZ or mectin (ML) drenches. Yarding of stock (in particular young stock) also greatly enhances “oesophageal groove” reflex causing drench to bypass the rumen. This probably negates any benefit gained by the slowing of food in the gut caused by yarding. Good drench technique and low-volume drenches also minimise the stimulation of rumen bypass.

Much more importantly, prolonged yarding of stock significantly enhances the risk of contagious disease, for example, mycotic dermatitis and pneumonia: both major problems in lambs and hoggets.