Quarantine and drench returning sheep
Farmers are being reminded to treat all incoming sheep with a Group 4 or 5 wormer and quarantine them to prevent resistant worms being brought on farm.
It is common practice to treat and quarantine newly purchased stock but this process can be overlooked when it comes to sheep returning from grazing.
Nick Burford, strategic account manager for Elanco Animal Health, said it was vital not to forget as they pose the same risk as newly bought stock.
He said: “Whether sheep are grazing common land or rented ground, unless a farmer has had sole use of it for a minimum of two years, it’s important to treat the sheep as ‘incomers’.”
Currently there are only five chemical groups of wormers and research shows resistance to group 1-BZ (white), 2-LV (yellow) and 3-ML (clear) is growing rapidly.
“Once farms have resistance there is no way back and it can make it extremely difficult for that farmer to control worms, so protecting the efficacy of wormers is vital,” warned Mr Burford.
The best practice protocols for quarantine dosing:
1. Weigh stock and calibrate drenching equipment
To ensure sheep are dosed accurately, don’t guess their weight. Calibrate your scales, then select and weigh the largest sheep in the group and treat all sheep according to the heaviest. Underestimating the weight can cause sheep to be underdosed. Ensure dosing guns are administering the correct amount of product by calibrating the gun. Apply the product over the back of the tongue to ensure each animal swallows the full amount.
2. Treat all incoming stock with group 4 or 5 wormer
Treating your flock with a product from one of the newer wormer groups, such as Zolvix, will help to clear out any resistant worms that have been left from previous treatments from older group wormers and will support improved growth rates, helping to slow down the spread of resistance.
3. Quarantine sheep
Ideally sheep should be treated with a Group 4 or 5 wormer as they leave grazing and subsequently kept off new pasture for 24 to 48 hours. This will allow the wormer to work and prevent worm eggs from being passed onto pasture.
4. Turn sheep out to ‘dirty’ pasture
If this is not possible, the wormer should be administered as soon as possible on return, before turning out onto ‘dirty’ pasture.
All treated sheep should be turned out onto pasture that has been recently used by the resident flock. The aim here is that treated sheep should pick up a small number of the farm’s ‘normal worms’.
If any worms do survive the quarantine treatment, this will effectively dilute those survivors and minimise the risk of developing resistance to the quarantine treatment.
