A negative fecal doesn't necessarily mean he is actually negative for parasites. There are a few parasites that will not show up on fecals, namely small strongyles, pinworms, and tapes.
I actually just had to adjust my deworming (because I was deworming according to fecal) and both horses had clear fecals, but I found an adult pinworm in my geldings manure and evidence of pins around his anus just a month after a generous deworming with equimax. So I dosed both with Quest and found 1 pinworm in some manure, but what surprised me was my filly had had a fairly significant small strongyle infestation that neither the fecal showed, nor the equimax took care of just a month before. Never again going by fecals only... And my horses will be dosed with Quest at least once a year, obviously there is ivermectin resistance, Quest is the only dewormer with no known resistance, you just need to be more precise with weight. My filly lost her "hay belly" after I got rid of the small strongyles that I didn't know were there because fecals didn't tell me, and previous ivermectin/strongid/safeguard doses didn't get them.
That being said, pay attention to protein as already stated and sand if you live in an area with sandy soil and often feed off the ground or have overgrazed pasture (biting the grass too close to the ground is another way they ingest sand)
Last edited by Blue Smoke; 08-28-2013 at 02:29 AM.