Using FEC as a monitoring tool

Faecal egg counts are a good tool for monitoring the need for anthelmintic treatment in horses throughout the grazing season. 

Individual horses handle roundworm infections differently, some have a high egg count (high shedders), whilst others with the same number of adult worms inside will maintain a low egg count (low shedder). This is due to the individual horse’s immune system.

Conducting frequent egg counts can identify high shedders, combine this knowledge with the risk factors described below and you can design anthelmintic (wormer) treatment programs which ensure your horses stay healthy and pasture parasite contamination doesn’t get too high.

Questions faecal egg counts can answer:

	Are roundworms the problem? Evidence-based treatment establish whether roundworms are the cause of poor conditions and diarrhoea confirm the presence of adult roundworms to inform treatment choice Testing could save the time and costs of worming horses if roundworms are not the problem
	When to treat? Regular egg counts ~2-4 weeks apart Frequent monitoring can provide an indication of which paddocks are more wormy Highlights the optimal time for treatment Can be useful to improve health and welfare Correct timing = greatest benefit from wormer treatments
	Which animals to treat? Treating only those horses which need treatment reduces excess chemical usage and costs. This will also reduce selection pressure for anthelmintic resistance
	Did the treatment work? Only viable test to check if anthelmintic treatments are working Avoid wasting money on treatments which are ineffective Wormer resistance is common – understand what works in your stable to treat effectively
	What egg counts CAN’T tell you… Egg counts cannot tell you about encysted larvae as only adult worms produce eggs (see types of worms for more information)  A single faecal egg count only provides a snapshot of what is happening…frequent testing is required to maximize benefit Egg counts can’t tell you which types of worms are present Egg count results do not always reflect the number of adult worms in the horse Different types of worms producing different numbers of eggs Some horses can maintain good condition and have low egg count despite harboring worms (resilience)

Click here for further information on targeted roundworm control in horses.