11 Feb Can you offer guidelines for collecting fecal egg counts in sheep?
Answer: If there is one animal with Barber Pole eggs in the feces, assume that all sheep are exposed and that vigilance is a priority.
Barber Pole Worm is a “warm-season” parasite. Take fecal egg counts in late spring through early fall. In the Intermountain West, it usually takes a minimum of 45 days on irrigated pasture for Barber Pole Worm infections to become significant.
Don’t take fecal egg counts within four to five weeks after deworming unless it is for a Fecal Egg Count Reduction Test (10 to 14 days). The dewormer will (hopefully) reduce the Barber Pole Worm populations in your sheep until they are re-infected.
Hypobiosis of late stage (L4) larvae occurs in the ewe through the winter. The parasites are in an arrested state in the abomasum with no eggs being shed. Taking FECs in winter is not predictive of summer egg counts. Sheep must go through periparturient rise (see The Periparturient Egg Rise, from the American Consortium for Small Ruminant Parasite Control) and be out on pasture for a FEC to be indicative of animal and pasture parasite loads.
It is best to collect a fresh sample by inserting a gloved, lubricated finger into the sheep rectum. Pull out about two to four grams. Record the animal’s FAMACHA score. If this is not possible, corral the sheep for an hour, let them lie down, and then get them up. There will be a number of fresh fecal samples that you can scoop up off the ground. For the complete procedure of collecting a fecal sample, see the video Why and How to do Sheep and Goat Fecal Egg Counting, by the University of Rhode Island.
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