Seven out of 10 farmers incorrectly guessed the weight of sheep during a recent exercise – which can result in the drugs being ineffective when treating worms.
A “guess the weight of the sheep” competition run by Hybu Cig Cymru – Meat Promotion Wales (HCC) at the Royal Welsh Show showed that around 70 per cent of competitors underestimated the weight of the pen of lambs.
“Underestimating the weight of sheep can result in too small a dose of wormer being administered which can encourage the development of resistance to the drug,” said Charlotte Morris, HCC’s Industry Information Officer.
“A recent project overseen by HCC indicates the resistance to wormers, including those previously considered effective at eradicating parasites in sheep, is increasing in Wales.
“It is therefore important to ensure when drenching, farmers are using the correct dose required by those sheep.”
HCC advises that correct drenching procedures are carried out including selecting and weighing the biggest sheep in the group and using the dose recommended for the whole group.
“If the weight range means that the lightest sheep will receive more than a double dose of wormer; divide the sheep into two groups based on size and work out the dose for each group based on the heaviest for each,” said Miss Morris.
“It’s important to check that the weigh crate and drenching gun are calibrated before you start.
“The purpose of the competition at the Royal Welsh Show was to highlight the importance of knowing the weight of sheep to ensure they receive the correct dose,” said Miss Morris.
“The competition demonstrated that it is very difficult to estimate the weight of sheep by eye. Dosing sheep is expensive and time consuming and those farmers who are guessing the weights incorrectly are wasting both their time and their money and have the potential to increase the worms resistance to drenches on their farm.”
The four winners of the daily competition at the show and who each who received a high-specification drench gun for correctly guessing the weight of the sheep are Geraint Mathias of Powys; Sam Taylor of Denbighshire; Andrew Taylor of Powys and Lewis Jones of Pembrokeshire.