Conducting a fecal egg count reduction test
The problem of internal parasites developing resistance to dewormers is growing throughout the world. To determine the effectiveness of an anthelmintic, conventional or alternative, used on farm, a fecal egg count reduction test (FECRT) can be performed. The FECRT will assist the producer in determining the percentage of reduction of internal parasite eggs due to the anthelmintic treatment.
The steps in conducting a FECRT are as follows:
- Use a minimum of 12 - 24 animals depending upon herd size.
- Divide the animals into a control and a treatment group.
- Collect fecal samples from all animals.
- Deworm the treatment group animals based upon liveweight.
- Conduct fecal egg counts on all collected samples (Time 1).
- Between 7 and 10 days after deworming, collect fecal samples from all animals in both groups (Time 2).
- Conduct fecal egg counts on all samples.
- Calculate the percentage reduction in fecal eggs as follows:
FECR (% reduction) = ( 1 - ----- ) × 100
Where T2 is the average fecal egg count of all treatment animals at Time 2 and C2 is the average fecal egg count of all control animals at Time 2. A reduction of less than 95% is evidence of anthelmintic resistance. If the fecal egg count reduction is less than 65%, the dewormer is not effective.