Updated Parasite Guidelines for Horses Released by AAEP

The American Association of Equine Practitioners (AAEP) recently released updated guidelines for managing internal parasites for horses. Parasites such as small strongyles and ascarids are rapidly developing resistance to many dewormers available on the market. This phenomenon, called anthelmintic resistance, is becoming of great concern to many veterinarians and equine professionals.

To try and slow the development of resistance, as well as manage parasite loads of horses, the AAEP updated and revised their "Internal Parasite Control Guidelines." You can find a free, downloadable PDF of the guidelines online.

Here are a few of the key takeaways from these revised guidelines:

1. Do not deworm adult horses with fixed intervals year-round; instead perform fecal egg counts on all horses to determine shedding category and deworm accordingly.
2. Deworm all adult horses 1-2 times a year. Only deworm high shedders (>500 eggs per gram) more often (additional 1-2 times).
3. Do not blindly rotate using different dewormers; use dewormers based on fecal egg count reduction tests (FECRT).
4. FECRT guidelines have been revised and are now based on an "eggs counted" principle. Check AAEP guidelines for specifics on how to conduct the new FECRT.
5. For senior horses (>15 years), be aware that some seniors can become high shedders, even if historically they were low or moderate shedders. It is important to check egg shedding categories regularly with senior horses and treat with dewormers accordingly.

Remember that the overall goal of managing internal parasites is not to eliminate them entirely, but rather to manage them so that they do not cause health issues for horses.