Equine deworming schedules vary depending on individual horses, environmental conditions and exposure to parasites, but ideally people deworm horses anywhere from a daily basis to every 2 months. Historically, veterinarians recommended deworming horses, using a syringe medication, at least every two months, and no less than twice annually. However, horse owners can use other deworming methods, such as keeping horse stalls clean, to reduce the risk of worm exposure.
As with other medications, dewormers work against certain parasites, which appear at different times throughout the year. For control against tapeworms, people often buy deworming packs, which contain different types of compounds. Dewormers generally come in three types of compounds: Pyrante, Benzimidazole and Ivermectin. Pyrante compounds are applied in either January or February and again in July and August. In March or April, and again in September or October, horse owners administer Benzimidazol. Lastly, Ivermectin is administered in May or June, and again in November or December.
While owners can follow their own deworming schedules, they should have veterinarians perform a fecal egg count every 1 to 2 years, say Drs. Foster and Smith, who are Wisconsin veterinarians. Having an expert review can help owners customize their horses' deworming plans to their specific needs.
In between wormings, people can add anti-worm additives to horses' feed for protection. They should clean horses' stalls at least twice weekly, and break up manure piles in pastures when in use. Rotating horses among pastures and grouping them according to worming schedule helps too.