Parasitic drug resistance is inevitable, it's a case of slowing the resistance as much as possible on farms - Teagasc
Given the evidence for widespread parasitic/anthelmintic resistance on dairy calf-to-beef farms in Ireland it is vital for farmers to implement practices to minimise or stop the anthelmintic resistance on farms, according to Dr. Orla Keane, of Teagasc.
Anthelmintic resistance is fast becoming one of the biggest challenges to face pasture-based farms, with studies showing an increasing level of resistance across the board of anthelmintics that are available today.
There are currently three classes of anthelmintics available for the treatment of gut worms in cattle, benzimidazoles (white drenches), levamisoles (yellow drenches) and macrocyclic lactones (clear drenches).
Anthelmintic resistance to all three classes of drugs has recently been found on Irish sheep farms; however, the extent of resistance on cattle farms was unknown until a a recent study carried out on 24 dairy calf-to-beef farms by Orla shows that anthelmintic resistance was consistent on many of the farms.
“Anthelminthic resistance is a heritable trait which worms pass onto their offspring, increasing the problem,” explained Orla, speaking at the recent National Beef Conference.
The study shows of the farms tested, resistance of benzimadole (white wormer) was found on 71pc of dairy calf-to-beef farms tested. Some 25pc of farms showed resistance to levamisole, while resistance to macrocyclic lactone was found on 100pc of farms for ivermectin and 75pc of farms for moxidectin.
According to the study, farmers should implement sustainable worm control strategies that delay the further development of anthelmintic resistance.
Speaking on how farmers can minimise the risk of resistance at farm level, Orla said that farmers, where possible should use grazing strategies to minimise the risk of infection, adding that farmers should neither over nor under dose.