Sheep FEC Calculator

McMaster Technique – Worm Burden Assessment

coded by T.Barker

Sheep ID/Tag Number:

Egg Count (eggs per gram):

Dilution Factor:

Test Date:

Sheep ID: –

Raw Egg Count: –

Eggs Per Gram (EPG): –

Test Date: –

Assessment will appear here

🔬 Common Sheep Parasite Eggs

Strongyles (Haemonchus, Teladorsagia)

Oval, thin-shelled, 70-85μm. Contains morula (cell cluster). Most common in UK sheep.

Nematodirus

Large, elongated, 150-200μm. Thick shell, single large cell. Common in spring in UK lambs.

Coccidia (Eimeria spp.)

Round to oval, 20-40μm. Contains 4 sporocysts. Causes scours, especially in housed lambs.

⚠️ Clinical Signs of Worm Burden in UK Sheep

Select parasite type for specific symptoms:

📊 UK Interpretation Guidelines

Low burden (0-500 EPG): Minimal treatment needed, monitor regularly
Moderate burden (500-1500 EPG): Consider treatment, especially in young/pregnant animals
High burden (>1500 EPG): Treatment recommended, monitor closely
Note: Thresholds may vary by season, age, and body condition. Consult your vet for farm-specific advice.

🧮 McMaster Calculation Method

Formula: EPG = Egg Count × Dilution Factor
Standard McMaster (1:50): Count eggs in both chambers, add together, multiply by 50
Example: 6 eggs counted → 6 × 50 = 300 EPG
Note: This calculator uses the standard veterinary McMaster technique as recommended by UK parasitology labs.