More information

For further advice on medicated grit use and monitoring of strongyle worms and worm eggs, please contact:

Game & Wildlife Conservation Trust Upland Research Group,
Eggleston Coach House,
Eggleston Hall,
Barnard Castle,
Co. Durham,
DL12 0AG

Tel: 01833 651936


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Download a copy

A PDF copy of these guidelines is available to download.

Best practice checklist

  1. Conduct both early and late-autumn counts of adult strongyle worms from at least 20 adult grouse per beat. If they are low to moderate, then consider delaying the decision on whether to medicate until counts of worm eggs in grouse caecal pats (faecal egg counts) are conducted in late winter or early spring.
  2. Whether to use medicated grit should be based on not just the mean value of worms from sample counts but also on the spread of values across the sample. Also consider grouse densities and age structure, weather patterns and moor location.
  3. Avoiding over-exposure of worms to medicated grit is critical and may help delay the onset of resistance to the worming drug.
  4. Medicated grit is only available under licence administered by a veterinarian. Evidence of strongyle burdens that are likely to impact on grouse are required before a prescription is provided.
  5. Comprehensive records of medicated grit use must be kept and include:
    • Date and quantity of medicated grit purchased
    • Manufacturer
    • Batch number
    • Expiry date
    • Date placed on moor
    • Location of all grit stations (GPS locations if possible)
    • Date of withdrawl
    • Date of first shoot
    • Date and disposal method of old medicated grit
  6. Provide a grit site per spring territory. Estimate the grouse density by conducting spring and July grouse counts. Use small trays (20x15cm) to help prevent birds defecating in them. Trays should have good drainage by slightly raising them or putting on a gravel base. Avoid gritting on areas with standing water or proximity to running water. Faecal material should be removed from trays on a regular basis. If required, relocate trays 2-3m if faecal contamination is a problem.
  7. Only place about 500g of medicated grit in each tray as that quantity will last a pair of grouse about seven months.
  8. Remove all old medicated grit from the tray, remove it from the moor and dispose via a licensed waste disposal contractor. Clean grit trays. If possible, remove them and wash to reduce the possible spread of cryptosporidia. Medicated grit should only be available to grouse after shooting has ceased. A more targeted, shorter period would be better, but only when needed.
  9. To comply with the law, medicated grit should be withdrawn at least 28 days before the start of shooting to prevent the drug entering the human food chain. Once medicated grit is withdrawn, ensure grouse have access to plain quartz grit.
  10. When not using medicated grit, including during the shooting season and 28 days before shooting commences, supply grouse with plain grit. Place approximately 500g of plain quartz in a clean tray, if necessary 2-3m from the medicated site if contamination with faecal material is a problem.

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✓ History of disease
✓ History of control
✓ Medicated grit
✓ Assessing grouse for worms
✓ Deployment of medicated grit and grit box hygiene
✓ Best practice checklist

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