Underestimating stock weight could contribute to anthelminitc resistance

A large proportion of farmers could be underestimating the weight of their stock and contributing to a rise in anthelmintic resistance, according to findings from vet pharmacy, Murray Farmcare.

62% of respondents asked to guess the weights of two Suffolk lambs and a Suffolk ram at Dumfries Agricultural Show underestimated the true figure by an average of -17%, -20% and -25% across the three animals.

Resistance of worms to anthelmintics, particularly in sheep, is now a major concern to the farming industry, and one of the main contributors to the development of resistance to wormers is underdosing – when wormers don’t work farmers have a real problem and a commercial threat.

Matt Colston, president of the Sheep Vet Society, said these results emphasise the need for even experienced shepherds and stockmen to weigh animals before treatments are given.

“Anthelminthic resistance is the most serious problem to face the sheep industry for many years. A complete change in attitude towards worm control is needed if we want wormers to be effective in the next ten years.

“Under-dosing, repeated use, using the wrong product at the wrong time and bringing in resistant worms with bought in animals are just a few of the factors that allow the development and spread of anthelminthic resistance.”

Speak to your vet or SQP to set up a worm control programme for your farm that follows the advice of SCOPS (Sustainable Control of Parasites in Sheep).