The Equine Expert

Deworming Horses – The Ins & Outs
By Tanja Schnuderl

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Deworming horses is an essential part of their healthcare routine to prevent and control parasitic infections. Here are some general guidelines for deworming horses:

  1. Consult with a veterinarian: It is crucial to work closely with a veterinarian to develop a deworming program tailored to your horse's specific needs. They can perform fecal egg counts and provide guidance on which deworming products to use and when.
  2. Create a deworming schedule: Establish a regular deworming schedule based on the recommendations of your veterinarian. In the past, traditional programs involved deworming horses every 8-12 weeks. However, due to concerns about parasite resistance, many veterinarians now recommend targeted treatments based on fecal egg counts.
  3. Fecal egg counts: Periodically collect fecal samples from your horse and have them analyzed by a veterinarian. Fecal egg counts determine the number of parasite eggs present in the horse's manure, which helps identify the need for deworming and the appropriate type of dewormer to use.
  4. Select appropriate deworming products: There are several classes of dewormers available for horses, and each targets different types of parasites. Your veterinarian will recommend the most suitable deworming products based on the results of fecal egg counts and the specific parasites in your area.
  5. Rotational deworming: In the past, rotational deworming was a common practice, where different classes of dewormers were used in rotation. However, due to increasing parasite resistance concerns, many veterinarians now advocate for targeted deworming based on fecal egg counts rather than routine rotation.
  6. Proper administration: Follow the instructions provided by the dewormer manufacturer and your veterinarian for the correct dosage and administration method. Dewormers are typically administered orally as a paste or gel, although there are also other formulations available.
  7. Pasture management: Good pasture management practices can help reduce the risk of parasite transmission. Regularly remove manure from pastures to minimize parasite contamination and consider rotational grazing or giving pastures a rest period to break the parasite lifecycle.
  8. Quarantine new horses: When introducing new horses to your property, it is important to quarantine them initially to prevent the spread of parasites. Have them thoroughly examined by a veterinarian and follow their recommendations for deworming and monitoring before integrating them with other horses.

Remember, deworming practices may vary based on regional factors, horse health, and parasite prevalence, so it is crucial to work with a knowledgeable veterinarian to create an effective deworming program for your horses.

Tanja Schnuderl is the Director of International Services with The Equine Expert LLC, a multi-discipline equine expert witness and consulting firm with expert equestrians offering legal expert witness and consulting services in court cases and legal matters. Tanja is an expert on Barn Management and Horse Behavior. She was the barn manager at several boarding facilities and a private training facility of a FEI Dressage rider before taking over as Director of The South Carolina Equine Park, an established multi-discipline equine facility which hosts about 30 horse competitions each year. She has established her own equine appraisal company, Sigma Equine LLC. Tanja grew up in Germany and was a paralegal for many years.  For more information on Tanja Schnuderl email,


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