Most adult horses only need to be dewormed once or twice a year, typically in the spring and fall, based on fecal egg count (FEC) results that measure the number of worm eggs shed in their feces
. This baseline deworming targets large strongyles, ascarids, and tapeworms. However, the frequency can vary depending on the horse's parasite egg shedding level:
- Low shedders (less than 200 eggs per gram of manure) generally require 1-2 dewormings per year
- Moderate shedders (200-500 eggs per gram) may need 2-3 treatments annually
- High shedders (over 500 eggs per gram) often require 3-4 or more treatments per year to control parasite loads effectively
Foals and young horses need more frequent deworming, often every 2 months during their first year, due to their higher susceptibility and parasite exposure
. Veterinarians recommend using fecal egg counts to tailor deworming schedules individually, avoiding overuse of dewormers and reducing resistance risk
. Additional factors influencing frequency include geographic location, climate, pasture management, and seasonality of parasite transmission
. In summary:
- Adult horses: typically 1-2 times per year, adjusted by FEC results.
- Moderate to high shedders: 3-4 times per year.
- Foals: every 2 months during the first year.
- Always consult your veterinarian for a targeted program based on fecal tests and local conditions
