Farm Table says:
What is the problem?
Producers had a number of registered veterinary chemicals at their disposal with which to manage internal parasites in goats, but they all stemmed from technology more than three decades old and were all blighted by varying degrees of drench resistance in the nematodes they aimed to control.
The efficacy of 3 anthelmintics registered for use in goats, oxfendazole (OFZ), morantel citrate (MOR) and abamectin (ABA) were assessed individually and in combination against resistant strains of Haemonchus contortus and Trichostrongylus colubriformis over 3 experiments.
What did the research involve?
For each experiment, Boer cross goats were sourced from a local supplier, treated to remove helminth parasites and then infected with 4000 L3 H. contortus Gold Coast 2004 and 8000 L3 T. colubriformis Gold Coast 2004.
Faecal worm egg counts (WEC) were carried out at Days 25, 28, 32, 35, 39 and 42 post infection.
Anthelmintic treatments were applied after allocation to groups after WEC at Day 28 and slaughter of all goats for worm burden estimation occurred on Days 43-44.
What were the key findings?
This study has shown that the anthelmintics registered for use in goats when used alone are likely to have limited efficacy against contemporary strains of gastrointestinal nematodes with the exception being MOR against susceptible populations of H. contortus.
A more accessible and less expensive MOR product would be highly desirable in these situations compared to the version used in these trials which is the only product currently on the market.
When dosing goats, operators should be careful to place the dose over the back of the tongue to ensure delivery of the full dose to the rumen or abomasum.