Anthelmintic Resistance
By Dr Mackie Hobson BSc(Agric),BVSc

1. Diseases

Determine the Resistance Status on Your Farm

The first step in combatting the problem is to determine the current status on a farm. Every farm is different and resistance levels will depend on previous management strategies. Due to the economic implications of roundworms, it is best to find out in as much detail as possible what the situation is on individual farms specifically with regard to the status of roundworm resistance.

To check for dose resistance in a flock, do a Faecal Egg Count Reduction Test (FECRT).

• Take a pooled faecal sample from about 5 marked goats. Keep the faecal sample in the fridge and get your vet do a FEC (faecal egg count) within 48 hrs. 
• Dose with an anthelminthic if indicated, recording the product used.
• Take another sample from the same marked goats 10-14 days later and have a FEC done.

Any roundworm eggs that are found in this second sample must have come from worms that survived the anthelminthic dose as it takes at least 21 days for ingested infective L3 stage larvae to start producing eggs.

See ‘ Roundworm Managements’ on the website