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Using anthelmintics

Anthelmintic (wormer) groups

Anthelmintic  Symbol
Benzimidazole (BZ)

(Fenbendazole)
Tetrahydropyrimidines (THP)

(Pyrantel)
Macrocyclic lactone (ML)

(Ivermectin/moxidectin)

NOTE: Only moxidectin and 5 day courses of fenbendazole are effective against encysted stages of small redworm

REMEMBER: Resistance develops to the group, not the individual product

Dosing correctly

  1. Estimate horse weight using a weight tape or scales: calculate dose based on individual animal weight (click here for more info on how to weigh your horse and why it is important)
  2. Ensure products are stored correctly 
  3. Administer treatment correctly: restrain the horse and ensure it swallows the full dose
  4. Check the treatment worked: testing ensures you only use anthelmintics which work for your animals

 

How to check if an anthelmintic treatment worked

Faecal egg count reduction test (FECRT) compares the egg count before treatment and 10-14 days later to calculate reduction in egg output.

An early warning sign that resistance is emerging is that parasite eggs begin to appear more quickly after treatment (egg reappearance period). Frequent faecal egg counts (from 5 weeks post treatment) will alert you to a shortening egg reappearance period and the potential development of anthelmintic resistance.