[Lynnwood]

One of my BO's older mares (18) has the most foul smelling manure I have ever experienced. It smells nothing like horse manure the piles are BIG and semi formed. Both the smell and the texture are not usual for this mare. She has not had a huge feed change just an increase in O/A by a flake sometimes two during the winter. Over the summer the grass is lush and she gets cut way back shes a super air fern.

Mares BAR no change in attitude or behavior.

Any ideas what might be causing the change in smell and texture?

[deltawave]

Most really vile poop smells (as opposed to just normal poop smells) are the product of increased anaerobic bacterial activity or volatile compounds being formed in the (usually large) intestine. Which is NOT to say that it means anything pathological is going on--intestinal flora vary in response to what is being eaten and also in response to anything else that affects their environment, like drugs, antibiotics, sudden changes, etc. I've noticed sudden, hideous poop smells in a horse after surgery, and also in one after foaling--both returned to normal within a few days without any specific intervention. Both horses were fine otherwise. (other than the one having had surgery--on a foot) Loose poop might be a different story and I've not really had any with that problem other than every now and then. I guess you'd want to do the usual detective work--worms, teeth, something in the hay, etc.

[Underthebridge]

Giardia maybe, I don't know if there has to be runny manure and weightloss.

[alterhorse]

If by O/A you are saying orchard grass alfalfa mix, then note that alfalfa can make horse poop smell like dog poop.

You could try a probiotic just to see if it helps.

[Underthebridge]

just curious if the alfalfa is very green?

[Lynnwood]

No the hay is very moderate. I'd warrant about a 70/30-O/A mix if that. The alfalfa doesn't seem greener then normal.

[TheJenners]

What about grain?

I've encountered two different times, two different horses, two different breeds and ages, who had horrible smelling poop, like literally smelled like dog crap. Really, really bad dog crap. Both of the horses were on Cool Calories.

[SCMSL]

My horse's first symptom of an ulcer flare up is soft poop (not diarrhea, as much as just a very soft poop) along with the worst smell I've ever experienced.

Might be worth checking...

[JB]

Every horse I know that has had that nasty smelling poop, which granted has been just a handful, has had ulcers.

[LauraKY]

Every horse I know that has had that nasty smelling poop, which granted has been just a handful, has had ulcers.

Is it that sickly sweet smell?

[Meadow36]

I would probably start with a fecal FEC, and deworm as necessary.

[cai]

Is the horse on MSM? Some--but not all, IME--can have a distinctive, sulfuric smell when on it --very funky!

[horsepoor]

Every horse I know that has had that nasty smelling poop, which granted has been just a handful, has had ulcers.

This is interesting because I was just going to post that when I have noticed stinky poo around here, it was when the horse was on omeprazole FOR ulcers. Not just mine, but others in the boarding barn I was at. Didn't notice it before or after the course of omeprazole.

[reay6790]

My horse's poop smelling WONDERFUL and he is on a small amount of omeprazole ... said the most unbiased mother ever... :/ heh

[AliCat518]

My gelding was on stall rest following (tendon sheath) surgery when he developed awful smelling poop. He was on ulcergard, bute and antibiotics. I used Probios and his poop was back to normal within a day.

[JB]

Is it that sickly sweet smell?

Yes, it's that sickly sweet smell

[pony baloney]

Is the horse on MSM? Some--but not all, IME--can have a distinctive, sulfuric smell when on it --very funky!

Yes, my horse has that. Ultra smelly farts too.

[deltawave]

The one I mentioned who'd had surgery was on omeprazole post-op. Poop smelled like mothballs. I've given him omeprazole since, however, with no stink. My guess is it was the anesthetic and maybe the antibiotics he got that tipped the intestinal apple cart briefly.

[Lynnwood]

Ok so to narrow it down. The mare is on a tiny amount of Senior 400g am/pm. She is out on grass /actual grass all be it brown dead in FL right now about 8-10 hrs a day in the summer she's out all night.

When she comes in at night she gets a few flakes of O/A and Coastal.

She is on MSM.

She has a pretty cushy life is a trail horse, ins't asked for anything strenuous , goes over night camping a few times a year. Not the lifestyle I'd equate with ulcers.

Is de wormed regularly , BO is meticulous about pasture care and they are picked and dragged monthly. Stall manure is taken away via dumpster. Its a running joke daring someone to find horse poop on the property.

She is such an easy keeper that normally over the summer when the grass is lush she is cut back to one or no O/A and just gets coastal. She ends up tick fat even on that.

So the only change is the addition of extra O/A but the consistency change and smell are recent not when her hay was increased.

[LauraKY]

Yes, it's that sickly sweet smell

Could be any number of things...and it could be contagious. I'm saying COULD not is. It could certainly be something else, but I'll bet you anything there's some kind of bacterial imbalance going on in the gut.