It really depends on what his turnout is like. Is he with other horses? If so are the all on the same worming rotation? Is the paddock mucked regularily? Is the horse stalled often? How old is he/she?
I used to have fecals done twice a year before I acquired 3 more horses :roll:(Can't have just one!!!!!) Then I'd base my worming shedule on the worm count and what type. Worming every 6-8 weeks is just a general rule of thumb, but now a days it just helps the horse build a resistance. That's why IMO fecals are important, therefor you aren't over or under worming.
If fecals are not an option, seasonally should do the trick. It also depends on the location. In warmer climates you'd typically want to worm more often (again, depends on the turnout, etc), but in those with extreme heat or below zero, worming less often is O.K.
My herd of 4 is on a dry 6 acre lot that is mucked out every 2-3 days. I usually do a Fenbendazole in the middle of winter, Moxidectin in spring, Ivermectin in summer, and Pyrantel Pamoate in fall, then repeat if my fecals come back low.
Butch is stalled every night for about 10-12 hours and he is 9. I can't get a vet out for at leas two weeks, I guess due to it being show season. There are only 3 close and that is the soonest I could get a farm call that was non emergency, for a fecal. I would much rather be on the safe side and get the fecal, just to see, because I didn't even THINK about them building up a resistance to the medications. DUH!:roll:
Abbey, seriously, you are a total LIFE saver! I really do appreciate your replies so much!