UK producers, animal health advisers, and vets should be on the look-out for signs of resistance to triclabendazole (TCBZ) in cattle according to Merial Animal Health Veterinary Adviser Callum Blair.
He says: “History has taught us that in parasitology what happens in the Southern Hemisphere will almost inevitably be a problem in the future in the UK. There are an increasing number of reported instances of triclabendazole resistance in beef and dairy cattle in Australia and South America.”
A recently published study from Australia showed resistance in naturally infected beef and dairy cattle1. Research was conducted on seven south-eastern Australian beef farms, and one dairy farm where treatment failure by TCBZ was suspected. On each farm fifteen animals were treated with TCBZ and fifteen were used as controls. Resistance was detected on the dairy farm and on four out of the seven beef farms. The study concluded that the results suggest that TCBZ resistance is widespread in cattle in south-eastern Australia.
Research conducted in dairy cattle in Peru2 and in cattle in Argentina3 also showed signs of resistance. In the Argentinian study TCBZ treatment had no effect even at double the recommended dose.
Callum says: “This is an important issue, particularly for producers farming both sheep and cattle. We need to preserve TCBZ for use against immature fluke in sheep as they cause the potentially fatal acute form of the disease. Liver fluke is the same parasite in both species and the spread of resistant fluke from one species to another could have damaging consequences. It’s important for producers to develop a treatment regime with their animal health adviser or vet which addresses this issue, and uses alternative solutions for cattle.
