Don’t let worms ruin your margins

Millions of pounds a year is being lost to worms, with the financial loss from liver fluke in sheep alone costing 1.5m last year from condemned livers, according to recent figures from EBLEX.

But with liver fluke just one of several worms affecting sheep and cattle, the costs implications are sure to be higher from animal deaths and poor performance, says consultant vet Tony Andrews.

“It can sometimes be underestimated the damage worms can do. Worms reduce the ability of animals to deal with disease and to grow, which ultimately can impact on the bottom line,” he says.

And even though the peak infective period for this year is over, worms can stay active quite late in to the season, says independent sheep consultant Lesley Stubbings. “Now is the time when you could get caught out. Trichostrongylus (black scour worm) in store and replacement lambs are often seen in late autumn/winter which is why faecal egg count monitoring of batches of lambs is vital,” she says.

Fluke is also high in people’s minds and Ms Stubbings warns about withdrawal periods. “Be aware about withdrawal periods and monitor for fluke using faecal egg tests.”

And faecal egg monitoring youngstock can also help determine where to graze animals next year, adds Mr Andrews. “When you have a high worm burden in young animals this year don’t graze youngstock on the same fields next year. Monitoring helps build up an idea of how vulnerable you are and can help prevent unnecessary worming which influences resistance.”

However, a combination of farm history and faecal samples should be used when deciding whether to worm, says vet Maarten Boers, The Livestock Partnerhip.

“When faecal samples are taken from first and second season cattle when housed sometimes false negative results can be produced. Some worms at this time of year, such as Ostertagia, go in to hibernation in the stomach lining as larvae, and so worm eggs aren’t produced.

“Ostertagia will still cause reduced production and when these larvae re-emerge in the spring it could cause type two ostertagiasis which causes stomach damage sufficient to cause weight loss, diarrhoea and death,” he says. Mr Boers recommends giving a housing dose of ivermectin pour on to cattle at risk.

And when the decision has been made whether to treat for worms, making sure animals aren’t stressed must be a priority, says Mr Andrews. “When worming animals at housing, a lot of things can be changing such as diet, environment, and husbandry. It’s important to keep stress low as it can affect the ability of some wormers to work.”

Trying to cut time and cost by administering a dual-purpose wormer is also something farmers should avoid unless both wormers are needed, adds EBLEX senior beef and sheep scientist Mary Vickers. “Products that combine a wormer and flukicide can often seem like an attractive option. However, they are often only of value when the cattle require treatment for both worms and fluke.”

A new guideline has also been produced for cattle which is based on the SCOPS principles for sheep, adds Dr Vickers. “Resistance is becoming an issue and the eight basic principles outlined in COWS (Control of Worms Sustainably), will hopefully help limit the development of resistance in cows.”

New guidelines for anthelmintic use and worm control in cattle (based on SCOPS principles for sheep)

1. Work out a control strategy with your vet
2. Use effective quarantine strategies to prevent the importation of resistant worms in introduced cattle
3. Test for anthelmintic efficacy on your farm
4. Administer anthelmintics effectively
5. Use anthelmintics only when necessary
6. Select the appropriate anthelmintic for the task
7. Adopt strategies to preserve susceptible worms on the farm
8. Reduce dependence on anthelmintics