Faecal Egg Count (FEC)Friday, 28th February 2020
By Dr Mackie Hobson
A number of Mohair farmers use faecal egg counts (FEC) as a management tool to determine:
- If internal parasite treatment is required. Used in conjunction with other tools such as FAMACHA, 5-point check or performance indicators.
- Egg counts aid in monitoring in a parasite control program in measuring the rate of pasture contamination.
- FEC can be used to determine resistance in selecting and culling goats (particularly rams)
FEC to Monitor Pasture Contamination
Monitoring FEC can provide valuable information on whether or not worm numbers are increasing on a pasture. Mohair producers can use this information to determine when to move animals off of a particular pasture to prevent them from developing high levels of worm infection before having to dose.
Remember don’t deworm and move camps simultaneously as this will lead to rapid anthelmintic resistance development.
FEC to determine which dose (drug) resistance.
Another use of FEC is in determining drug (dewormer) resistance by conducting a faecal egg count reduction test (FECRT).
Prior to treatment take faecal samples from market goats (at least 5) and again 10 to 14 days after treatment on the same goats.
FECRT indicates a level of parasite resistance,
- FECR > than 95% generally indicating that the drug is effective.
The following formula is used to calculate % of FECR:
% of FECR = [100 x (1 - Post-deworming FEC)]/Pre-deworming FEC
Even if a treatment is not more than 95% effective, the information is still helpful in determining which drugs to include in a combination treatment if you have multiple drug resistance.
FEC for Selection/Culling
Parasite resistance and resilience when dealing with a parasite challenge are both heritable traits.
Animals with consistently low FEC, low FAMACHA© scores and that rarely require deworming demonstrate signs of parasite resistance.
On the other hand, if an animal consistently has little to no indicators of parasitism (based on FAMACHA© /Five Point Check©), but has high FEC, it is considered to be resilient and contributes to pasture infestation. Even though both of these animals are productive, a resistant animal is most desired. Conducting routine FEC allows the identification of resistance or resilient animals to select for breeding.
For more info on selection of worm resistance in Angoras see https://www.angoras.co.za/article/breeding-worm-resistant-angora-goats#235
For more information on Roundworm management strategies see