Over the past decade our understanding of internal parasites has improved exponentially. By gaining a better understanding of the internal parasites that affect horses and their lifecycle. We are much more equipped to target them more precisely. In the past a rotational deworming schedule with frequent high doses of parasiticides was used, but we now recommend deworming based on fecal egg counts. Deworming based on fecal egg counts greatly reduces parasite resistance which has become a growing concern. At Northern Lakes Equine Practice, we follow the American Association of Equine Practitioners (AAEP) deworming guidelines. At spring and fall examinations a fecal is collected, tested, and deworming recommendations. 80% of horses only need to be dewormed twice a year. This saves money and needless exposure to parasiticides.