I have a 22 year old gelding that develops diarrhea from autumn through spring. More accurately, it's more like very wet, explosive gas that he expels. His stools are often soft, but not terribly loose. I've tried worming, extra psyllium, probiotics, changing hay, none of which alleviated his condition.

After recently beginning the fourth year of this seasonal distress, and after a lot of incorrect guesses as to the cause,I think I've finally pinpointed the culprit. I caught him eating the pine needles that had blown down from the pine trees that surround portions of his corral.

I called my vet to ask if there was anything he could recommend to counteract this problem, but short of raking the pine needles, he had no suggestion to offer. I do try and keep them raked now, and I have seen some improvement since, but I'm not necessarily around when they blow down, so there's only so much relief that will produce in the long run I'm afraid.

He's in a dry lot with constant access to turnout. His diet consists of about 80%/20% grass hay (timothy with some orchard) to alfalfa. He also gets about 1 lb soaked beet pulp shreds in the evening. He is fed 3X daily and is in excellent weight. I'm very careful to keep his weight under control due to his size, age and some minor arthritis (He gets a glucosamine injection once a month)so I'd rather not feed him hay free choice. Would you suggest any supplement that would counteract the gut irritation that results from the pine needles he ingests?

Where are you from? Prescott, AZ

How did you locate this forum? Was linked from an equine forum

Hi Nancy,

Pine needles, in general, are not toxic to horses. However, in large quantities, as you noticed, they can cause gastric irritation. Horses will generally not choose to eat them if they have more enjoyable things to eat, such as hay. So, the best thing for your gelding is to offer hay 24/7. I'm not clear why you are against this idea -- what a shot of glucosamine has to do with offering hay free choice. Perhaps you could explain your reasoning.

You see, your horse's stomach produces acid 24/7, unlike we humans who produce stomach acid only when we eat. Because of this constant acid production, it is essential that horses be able to trickle feed. This means that they need to chew constantly. Chewing produces saliva, which neutralizes stomach acid. If they are not able to do this, they often develop ulcers. One of the first signs of an ulcer is diarrhea.

So, whether it is an ulcer or simply an irritation, I would suggest giving him a double dose of Ration Plus to boost the health of the bacterial flora in his hind gut. This will help protect his digestive system and will very likely cure his diarrhea.

Thanks so much for writing. Please keep me posted on his progress.

All the best,

Dr. Getty

Dr. Getty, thank you very much for your response. I'll be sure to try the Ration Plus you suggested. Do I understand correctly that this will improve the conditions for the flora already in his gut? When this condition first presented several years ago, my vet gave me a supplement to increase his gut bugs. I fed it to him for several weeks, but didn't see any improvement. (Unfortunately, the name of it escapes me. It may have been available only by prescription.)

He's been diarrhea free for the last week since there have been fewer pine needles in his corral.

My comment about the glucosamine was simply in reference to how I treat his mild arthritis. My reasons for not wanting to feed free choice hay are that I've seen notable improvement in his overall comfort and movement since he's slimmed down to his present weight. He wasn't terribly overweight before, but he's a large horse-- 16hh and at 22, with his mild lameness, I worry about the additional stress that more weight could have on him.

When I spoke to my vet recently about the problem with the pine needles, I asked whether leaving straw available to him would be an option. My reasoning was it would be low value enough not to cause weight gain, but still satisfy his need to chew. But my vet recommend against that due to the possibility of it causing an impaction.

Where are you from? Prescott, AZ

How did you locate this forum? Was linked from an equine forum

Hi Nancy,

Ration Plus is not a live microbial product like the one you used before. Instead, it consists of fermentation products that feed existing bacteria in the hind gut, making them healthier and allowing them to multiply. This is much more effective than a probiotic that only supplies a small fraction of the many bacterial species that live in the hind gut.

About the straw -- actually straw has as many calories as hay, it's just higher in fiber and lower in nutrients. So, for weight loss, this would not be effective. And, your vet is right -- it can cause impaction.

I agree that it is good to keep him weight down, but letting hours go by without anything to nibble on can actually cause weight gain, oddly enough. This is because the stress of not eating causes an increase in blood cortisol levels, leading to excessive fat storage. Eating, on the other hand, actually stimulates the metabolic system to allow your horse to burn more calories.

I'm pleased to hear that his diarrhea has gone away now that he's not exposed to so many pine needles. If he should get diarrhea again, be sure to give him electrolytes to replace what he is losing.

Hope this is helpful!

All the best,

Dr. Getty