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How to deworm goats the smart way
The old advice — deworm the whole herd every few weeks on a fixed calendar — is now known to do real harm. Blanket treating drives dewormer resistance, the situation where the parasites that survive the drug breed and pass on their resistance until the product simply stops working. With only a handful of effective drug classes left for goats and no new ones coming, the goal today is to deworm fewer animals, less often, and only when they actually need it.
Know your enemy: the barber pole worm
In most regions the worm that kills goats is Haemonchus contortus, the barber pole worm. It's a blood feeder, so the damage it does shows up as anemia rather than the diarrhea people expect. It thrives in warm, wet, grazing conditions and can build to dangerous numbers fast in summer.
FAMACHA: treat the individual, not the herd
Because barber pole causes anemia, you can gauge worm burden by checking the color of the lower inner eyelid. The FAMACHA system scores that color from 1 (deep red, healthy) to 5 (white, severely anemic). Animals scoring 4 or 5 — and often 3 if also doing poorly — get dewormed; the robust, red-eyelid animals are left untreated on purpose. Those untreated animals keep a population of non-resistant worms in refuge, which is what preserves the drug's power for years to come. Pair eyelid checks with body condition scoring and a look at weight trends.
Deworm effectively when you do treat
- Dose for the real weight. Goats metabolize dewormers quickly; under-dosing breeds resistance faster than anything. Weigh the animal or use a tape, and ask your vet about correct goat dosing — many products are labeled for cattle or sheep.
- Give orally, over the tongue, for most goat dewormers (not pour-on), unless your vet directs otherwise.
- Rotate by class, not by brand name. Switching between two products in the same drug class does nothing.
- Don't move treated animals straight onto clean pasture — that seeds the clean field with only resistant survivors.
Strategic deworming only works if you track it: who was scored, who got treated, with what, and when — so you can spot the animals that need worming again and again (cull candidates) versus the ones that never do. GoatLog logs each dewormer per animal with the product and date, and flags who's overdue on the interval you set.
Open GoatLog — log dewormers per animal, free →