Anthelmintics are an important part of the toolkit farmers have available to control parasites in or on their cattle.  To ensure these products keep working effectively it is vital to use them in the correct way.

Products should be chosen to specifically target the parasite and life cycle stage present, the time of year and previous treatment history.  Even before a product is administered it is vital to ensure it is stored correctly and used before its expiry date. Dosing equipment should be calibrated before a treatment session.

Cattle should be dosed according to their individual liveweight if possible.  Under-dosing can lead to increased selection of drug resistant parasites and over-dosing may require adjustments to withdrawal periods and can cause toxicities in extreme cases. Adherence to dairy and beef withdrawal periods following treatment is vital.

If there are any concerns that a treatment has not worked, talk to your vet or animal health adviser about a post-treatment efficacy check.

    Cows Resources

  1. Integrated parasite control on cattle farms (COWS Guide, September 2023)
  2. Responsible use and disposal of parasite treatments (COWS, December 2022)
  3. COWS Guide to the effective use of cattle wormers. Worming - have you got it right? (Farmer leaflet updated Summer 2019)
  4. COWS Guide to taking a faecal sample to test for parasites (Summer 2019)
  5. Administering wormers anthelmintics effectively (COWS Guide, Dec 2014)
  6. Worming - have you got it right (Welsh) (Farmer leaflet)

    External Resources

  1. Parasite Control Guide 2022 (AHDB, A comprehensive list of products for the control of internal and external parasites in cattle and sheep)
  2. Annual review of Literature and Horizon Scanning Report 2019. Animal and Plant Health Agency Parasitology Group (November 2020)
  3. Annual review of Literature and Horizon Scanning Report 2018. Animal and Plant Health Agency Parasitology Group (November 2019)
  4. Farmers: check efficacy of treatment (Article for farmers)