Hi, my name is Janet. I have been boarding my friends horse for a little over a year.
He went from a mix of grass and alfalfa mix. He had too much alfalfa due to lack of grass. So his legs swelled up and we gave him butte. He did get better. We no longer gage him alfalfa. Kept him on a strict diet, but then he started get real runny. It's been a year. We've had him checked for worms. All O.K.
In spring and early summer I let him graze in my front yard and gave him carrots a few times a week. He was looking real good and had some shape to his stools.
My lawn slowed down and I ended up putting him back on a grass mix of oats and barley. Still runny and we don't know what to do. I have tried the probios, didn't do much. How can we get his stomach back to normal? Is he lacking enzymes that brake down the food? I did put him on a liquid vitamin 2 days ago. Should I start up the probios again, switch feed? Hope you can help,
thank you, Janet.

Hello Janet,

Since you’ve ruled out a parasite infestation, there are several points that can lead to chronic diarrhea. See if you relate to any of these:
1. Sudden changes in diet – for example, going from a rich pasture or hay (like alfalfa) to a poor quality hay. Or suddenly reducing the amount of fiber in the diet – this can lead to the disappearance of associate organisms in the gut.
2. Feeding contaminated silage.
3. Feeding excessive poor quality protein (alfalfa is not in this category since its protein quality is very high).
4. Improper worming regimen. A stool sample is not always a good indicator of the presence of worms. Larvae can migrate from the intestines, and therefore, a stool sample can come back negative, even though an infestation exists.
5. Overfeeding at one time. A horse’s stomach is really quite small. It is best to feed small, frequent meals.

Your horse is likely losing electrolytes, so I would suggest supplementing them until the diarrhea stops. Then you can switch to just adding iodized salt.

If his diet is deficient in calcium in relation to magnesium, and low in the B vitamins, digestive upset can occur. I would recommend a multiple vitamin/mineral supplement that also contains probiotics, such as Select II (for grass diets).

And, as an immediate treatment, I would recommend thiamin (vitamin B1). Do not administer IV or IM, since some horses have a negative reaction. Instead, I would add it to his food. You can buy Vitamin B1 by itself for horses, or even for humans, and crush the tablets. Give a dosage of 500 mg each day to start.

I hope this is helpful. Please keep me posted on his progress.

All the best,

Dr. Getty