Hello COTH. I am here to pick your brain…I have searched these forums and read everyone’s suggestions about diarrhea in horses.
I have a 27 year old warmblood gelding with no significant health problems who has had chronic intermittent diarrhea for the past 8 years. In the last year, the diarrhea has worsened in severity and frequency and can range from cow patty loose to firehose liquid poop. Metronidazole would clear it up, and it would return once the Metronidazole was discontinued. For 8 months, the diarrhea was completely controlled with Assure Guard Gold on the loading dose. I tried to taper to the maintenance dose and the diarrhea would return, so we kept him at loading dose and it was worth the fortune Assure Guard Gold costs to have a diarrhea free horse.
The Assure Guard Gold stopped working this summer and we went through the Metronidazole song and dance again. Of course, the Metronidazole clears it up, he stops it, it comes back. For a few months, the vet transitioned to Metronidazole as a spot treatment. Horse develops diarrhea, give Metronidazole. Discontinue as soon as diarrhea resolves. Wait to give Metronidazole until diarrhea develops again. Metronidazole works beautifully—Within 1 to 2 doses, he is back to normal and typically can last 10 days before needing another spot treatment. However, a few weeks ago, he developed firehose diarrhea, had an episode of mild colic that required a vet visit, and had persistent firehose diarrhea following. We reintroduced the Metronidazole, poop cleared right back up, left him on it for a few days longer since he had just had the colic episode, and then discontinued the Metronidazole. This time diarrhea returned within 2 days of discontinuing the antibiotic after normal, perfect poop in the AM and liquid cow patty poop in the PM. Today, we started with liquid sloppy poop and then 20 min later after getting out and moving his legs in the arena, he had a solid sort of normal small volume poop, then back to liquid sloppy cow patties the rest of the AM. His legs are a mess. His tail is a mess. He’s a stinky poopy mess. This is not fecal water syndrome to be clear.
He has seen the dentist who feels he has adequate grinding surface still. The vet sent out extensive stool studies that just returned. He says everything was normal. I have not seen them and have not had the opportunity to ask more questions on exactly what was tested. I know no values were reported on the bacteriology studies, but there was no Salmonella or C. perfringens. Just Enteric bacteria and E. coli were noted, which I know is typical in a normal horse. He was supposed to check for parasites as well… I will call Monday to get the other reports to see exactly what was tested. Unfortunately, I am often unable to answer the phone, so my mom is who gets the calls and doesn’t always know the questions to ask. I do not believe he has had any stool studies done specific to IBD. Definitely no ultrasound has been done.
He eats alfalfa, coastal hay, and a ration balancer. We are actually going to transition him to senior feed as the diarrhea and winter do cause weight loss and he would benefit from more groceries. He’s on Equioxx and Sucralfate daily. Aside from the colic episode the other week, he is generally unbothered. He is on well water, but it seems that the stool studies are all normal. The vet said potentially it could be the E. coli and suggested trying another 10 day course of Metronidazole and then treatment with Doxycycline. My gut is telling me this is not the right move— I am hesitant about the amount of Metronidazole this horse has been on, and I am concerned with hitting him with another antibiotic that could worsen his natural flora and complicate his diarrhea. It just doesn’t feel like the right move to me and like we’re poking around with a stick in the dark.
My differentials include:
IBD or some sort of mild colitis from long stem forage in an older horse
NSAID induced ulcers leading to diarrhea
Absolutely no good reason with no great solution leading to lots of stress and $$$ spent by his mother
Any thoughts would be greatly appreciated!! We’ve done the probiotics, we’ve done the Assure Guard Gold, we’ve done the bio sponge. If it exists, we’ve probably tried it. Thanks in advance!