Goat Dewormer Calculator — FAMACHA-Guided Targeted Selective Treatment

FAMACHA is a visual eyelid-color scoring system (1–5, red to white) developed in South Africa for identifying goats/sheep anemic from Haemonchus contortus (barber pole worm, the #1 gastrointestinal parasite of small ruminants in the US). Only animals scoring FAMACHA 3, 4, or 5 need deworming — the “targeted selective treatment” (TST) protocol. FAMACHA 1–2 animals have adequate red blood cell levels and should NOT be dewormed.

Dewormer resistance is widespread across US goat herds — some barns show < 50 % efficacy for benzimidazoles (Safeguard/fenbendazole) and macrocyclic lactones (ivermectin, moxidectin) due to decades of routine whole-herd dewormings. Routine whole-herd treatment selects for resistant worm populations and accelerates resistance. Targeted selective treatment (TST) of only FAMACHA 3+ animals preserves refugia (worms that weren't exposed to the drug) and slows resistance development.

10 mg/kg orally (higher than label dose for cattle — 5 mg/kg). Safe in all stages of pregnancy. Available as Safeguard Goat Dewormer (paste or suspension). Effectiveness against Haemonchus is declining in many US regions — confirm efficacy with a fecal egg count reduction test (FECRT) on your specific herd before relying on it. If FECRT shows < 95 % reduction, that drug class has lost effectiveness on your farm.

Rotate between drug classes, not individual products within a class. Three US drug classes for small ruminants: (1) Benzimidazoles — fenbendazole (Safeguard), albendazole (Valbazen). (2) Macrocyclic lactones — ivermectin (Ivomec), moxidectin (Cydectin). (3) Imidazothiazoles — levamisole (Prohibit). Use FECRT results to identify which class still works on your farm. Avoid combination products — use single-class products to preserve drug options.

Fenbendazole is safe throughout pregnancy. Albendazole is NOT safe in first trimester (birth defects, abortion). Ivermectin and moxidectin are safe in all stages. Levamisole is safe but narrow safety margin — accurate dosing critical. Always consult your vet and check the label for pregnancy warnings specific to the product.

Every 2–4 weeks during the grazing season (April through October in temperate US). Weekly scoring during high-risk periods (wet weather, new pasture, post-kidding). Monthly in winter when Haemonchus activity is low. Keep records — which animals repeatedly score 3+ are candidates for culling if you're running a production operation. Chronic high-FAMACHA animals increase farm-wide parasite pressure.