Reason for loose stool

Question
Adopted an underwt, neglected sr 14h QH in July. He gets 3 qts senior feed, fat supplement and probiotics in am and pm & timothy hay.Wormed w/ Ivermectin and strongid.Gaining weight.But has loose manure on and off regularly. Am going to Power Pack him. ANy other ideas. Thanks

Answer
Dear Nicole,

While it could be worms it is more likely either due to his gut flora being wiped out by the wormers or the fat supplement which often say on the label that they can cause loose stools.  If it were worms I would not expect the weight gain you've had.  I would do a fecal count before doing a power pack.  As you feed a probiotic I am leaning towards the fat supplement.  What is it and how much are you giving?  Personally I would cut back on the fat supplement and see if it changes anything.  Additionally I think there is plenty of fat in the senior.

Keep me posted,
Clair