horse grazing in the pasture
Since horses eat off the ground, sand can eventually build up in their gut and cause gastrointestinal issues like sand colic.

The Scoop on Horse Poop

Monitoring your horse’s poop is not for the faint of heart, but it is a good way to find out what’s going on inside his body. 

Handling horse poop may not sound appetizing to most people, but it’s part of Megan Petty, DVM’s, job at Tularosa Equine Clinic in Tularosa, New Mexico. Manure is a great indicator of a horse’s overall health, and a sudden change can be one of the first signs something is wrong.

Since many factors can affect the consistency of a horse’s fecal output, Petty suggested owners learn what is normal for their own horses. That way, they have a better idea of knowing when a change is significant enough to warrant a trip to the vet.

What is normal horse poop?

For horses, normal can vary depending on an individual horse’s nutrition. Horses require a diet of predominately roughage, and they should consume about 2 percent of their body weight per day, with 1 to 1.5 percent of that being roughage. A horse that eats lush alfalfa will have a much higher moisture content in its feces than a horse who subsists solely on coastal Bermuda grass hay.

Still, normal horse feces will look similar – individual fecal balls that all come out in one big clump together, with individual “apples” visible. The balls should have enough moisture that their contents stick together rather than crumbling and falling apart.

“Obviously the fiber is going to contribute to a better fecal output, but the kind of fiber the horse is eating makes a lot of difference,” Petty said. “For the most part, because the roughage is digested in the large colon – versus the grain that’s going to get digested in the small intestine – it’s going to be the roughage bulk in there that’s going to determine the appearance of it.”

Most grain will usually be digested and not visible in feces, although some pieces, particularly whole grains, can slip through. If a lot of grain is seen in a horse’s manure, this could signify a problem with his dentition.

“If I see whole grains of any kind in their manure, I start talking to clients about checking this horse’s teeth [to find out] why are those escaping through?” Petty said. “They should be chewing well enough to get those broken down enough that they can digest them and that they’re not shooting straight through them.

“Sometimes you see horses that are just ‘hoovering’ their grain,” she continued. “Those are horses that are going to be more so at risk of choking than the grains coming through in their manure whole being a problem. If their teeth are OK, maybe we need to figure out how to slow them down a little bit or get them something they’re going to be able to utilize [digest] better.”

The appearance of foal manure, like adult horses, also depends on the colt’s diet. A newborn foal that is eating a purely liquid, milk-based diet won’t have any form to its manure. Still, the feces should not be runny. It won’t have the formed fecal balls of an adult horse because there is no fiber base to it, but the colon will still absorb liquid, causing the foal’s manure to appear pasty.

horse poop chart

A baby’s manure will commonly be a yellow/orange color and will change as the foal’s diet matures. An early indicator of a problem, though, is a mustard yellow color.

“Mustard yellow is a pretty vibrant yellow, but some of the foals you’ll see have kind of orange-colored poop, especially if they’ve had plasma,” Petty said. “If we’ve administered plasma to a newborn foal, which is a pretty common practice where I am because rhodococcus [equi] is endemic all over this area, that will change the color of their manure because we’ve loaded them up and we’re kind of changing their whole immune system all at once.”

When a foal starts chewing on its dam’s hay or grain, that can cause a bout of diarrhea. If the foal doesn’t have a fever and is acting normal, the dietary shift is probably the culprit, but it is still worth investigating.

“The old adage about ‘foal heat diarrhea’ actually has nothing to do with the fact that the mare is in heat again and has everything to do with the lifespan and the age of the foal’s cells in their GI [gastrointestinal] tract,” Petty added. “They turn over when they’re about a week old, so they will get diarrhea because those cells have now changed. They’ve gone from being the early, ‘I’m going to digest colostrum and the first milk and be super efficient,’ and they’ve had a turnover of that gut lining, so now they’re figuring out how to digest with this new batch of GI cells.”

From apples to applesauce

Some horses naturally have wetter poop than others, but if a horse that normally has textbook, perfectly formed horse apples starts passing liquid feces, an owner should not hesitate to call in professional help.

“If all of the sudden your horse has the ‘pooping through the screen door’ pure water and it smells really bad, heck yeah that’s going to be cause for concern,” Petty said. “But, if your horse went out and grazed on lush green grass for half an hour today and it’s the first pretty, green grass, they’re probably going to have a little more moisture in their manure and maybe a little more manure because they bulked up. Diet really can influence that a lot.

“Knowing what’s normal is the biggest deciding factor on whether or not there is a problem,” she reiterated. “A horse can get loose, mushy manure from a trailer ride, and we call that stress colitis. It’s not a pathogenic thing. It’s not anything that’s going to create an issue for the most part. If it’s a horse that’s also having behavior changes and is colicky or has a fever, then absolutely even just a little manure change can be a problem.”

While people often picture diarrhea as mostly liquid feces, any manure that has extra moisture in it is technically classified as such. Diarrhea is typically caused by inflammation in the colon that’s not allowing the gut to absorb water appropriately. It can be a secondary issue from an infectious disease or be caused by parasites, or it might even be from getting too much phenylbutazone.

Some horses pass feces of a cowpie consistency, and while it can be caused by dietary changes, a fecal float will help determine if the cause is that new, lush alfalfa hay you just purchased or something like too much sand in the diet.

“If we rule out dietary changes – we’ve had the same hay the whole time, the same grain the whole time, no new nothing – then I will start the same way every time. I’m going to do a fecal, and I’m going to float it for sand,” Petty said. “I grab a poop sample, look at it under the microscope, and then I will grab a big handful of manure in a palpation sleeve and turn the sleeve inside out so now I have a bag with poop in the hand. I fill up the sleeve to above the thumb with water, and I squish up the poop and hang it on the side of my stocks or off the sideview mirror of my truck, and I let it sit. Sand is going to be the heaviest thing in that poop ball. I look in the fingers of the sleeve to see how much sand is in there.”

A little sand is common in most cases since horses eat off the ground, but if the fingers of the glove are full of sand, that’s a problem.

“You think about walking with sand in your shoe – it’s going to be irritating,” Petty said. “It’s going to rub, and it’s going to buff down the callouses on my feet from wearing boots all the time. The same thing happens in a horse’s gut. It rubs and irritates the gut lining so those cells are basically worn out and irritated and inflamed, and they can’t then absorb the water.”

It takes a lot of sand for it to start passing in manure because sand is heavy. The horse’s colon is large and sits at the bottom of the abdominal cavity; material inside must move uphill to get out. Therefore, the heavy sand mostly sits at the bottom of the cavity, so visible sand in the poop means the horse has a large sand burden in its gut.

While it makes sense to avoid feeding directly on a sandy surface by using a feed pan, oftentimes horses will flip them over and eat off the ground anyway. The best thing to do, according to Petty, is feed horses a psyllium-based, sand-clearing product, which will help bind up the sand and allow the horse to pass it. A cheaper option is to feed one cup of a fiber supplement like Metamucil twice a day the first week of every month, though some horses don’t like the taste.

When the going gets tough

While too much liquid in feces can be a bad thing, too little can be equally problematic. Hard, dry, small fecal balls can signify dehydration or an impaction.

“That’s usually what you’ll see first because they have sucked all of the water out of their body,” Petty said. “When a horse has got an impaction, they dump all their excess fluid into their gut to try to moisten up that fecal mass. They usually end up with the impaction because they’ve gotten a little dehydrated at some point, so their gut’s dehydrated. Then they’re dumping all their extra body water, all that extracellular fluid volume and everything else – they concentrate it and dump it all into their gut, which then dehydrates them further.”

plastic glove filled with horse poop
A fecal float, which Petty of ten per forms with a palpation glove, is an easy way to detect sand in a horse’s manure. The sand, which is heavier than any thing else in the poop ball, will fall into the fingers.

This is a vicious cycle, and when Petty sees a client in this stage, she pulls blood to measure how dehydrated the horse is, then palpates to see if she can feel the impaction. Next, she starts trying to rehydrate the horse.

Some people with colicky horses assume if the horse poops, it will begin to improve. That’s not always the case, Petty cautioned.

“There’s a whole lot of GI tract, and there’s a whole lot of GI tract that can be sitting behind where the problem is,” she said. “Yeah, they should still be able to empty out their rectum and their small colon, but if they’re dealing with a massive large colon impaction, they better be pooping out what’s behind it so they can start moving the impaction through.”

If an owner notices their horse has started passing small, dry poop balls but has no other symptoms, the best thing to do is encourage the horse to drink more water, Petty explained. This can be accomplished by adding salt to feed or by making a salt mixture to give orally. Take 15 cc of regular table salt, 15 cc of lite salt and mix them with something like carob syrup or yogurt in a syringe, then give it to the horse every four hours up to three times in a day. This should change their overall salt content enough that they begin to drink.

“On these really hot days when you come out and go, ‘[My horse] that likes to colic hasn’t drank very much water since last night,’ you can hit him with the salt mixture and just kind of preemptive strike them to get them to start drinking,” she suggested.

Unpleasant scenes

While it’s not pleasant to see your prized foal consume horse feces while frolicking in the pasture, it’s fairly common amongst youngsters. Known as “coprophagy,” there’s not a scientific explanation for it, but the general consensus is ingesting manure primes the foal’s gut by introducing the appropriate good bacteria in a high load to eventually help them digest solid food.

In adult horses, the practice is less common, and veterinarians tend to think it points toward a nutritional deficiency.

“Sometimes they’re missing something in their diet, so they’re trying to either eat their own manure to get it back or eating another horse’s manure to try to fill whatever that void is,” Petty explained.

Occasional bouts of coprophagy are generally not a problem – the horse may just be hungry or bored – but if a horse does it consistently, you may need to reevaluate his diet.

“We tend to forget that roughage is deficient in vitamins and minerals a lot of the time. That old ‘get fat on sagebrush and scenery horse’ that gets two flakes of hay in the morning and two flakes at night and is out on pasture can be lacking in its diet. If you see a horse eating poop, maybe it’s time to have a conversation with your veterinarian like, ‘Here’s what I’m feeding; what maybe are we missing?’” Petty advised.

Another insidious sight is worms in a horse’s poop. Strongyles, which are white, flat and pointed on one end, are common in adult horses, and ascarids, which are round and fat, are often seen in foal manure. Ranches with high parasite burdens are at risk of losing foals to ascarid impactions.

“If you find the adult worm, you can identify it and deworm appropriately,” Petty said. “Most of the time, you’re not going to see the worms. Doing a fecal float is, I think, of huge importance. I recommend doing it at least twice a year for our clients, because we’re starting to get big resistance issues with the dewormers, especially to ivermectin.”

A fecal float can include a McMaster egg per gram count, where vets take a diluted manure mixture and place it on a special grid, then look at it under a microscope. They count how many parasite eggs they see in each column, then determine the eggs per gram and deworm based on which worms and how many are present.

“You spend $25 at our clinic for the egg count, but if your parasite burden is low and you don’t have to go buy dewormer, you can actually save money,” Petty said. “If you can identify the actual parasite [in manure], that’s the easy way to do it. But more often than not, you’re not going to see them, so you have to go looking for them and figure out how many you have and [if] it is significant.

“If you have the clinical symptoms – the pot belly, the scruffy hair coat, the rubbing their tail – and you didn’t find anything in the manure, sometimes you’re still going to decide to deworm anyway.”

Most equestrians prefer to spend time with their horses rather than muck stalls, but once they learn what’s normal, a quick glance at their horse’s poop could be all that’s needed to know something’s wrong. That little bit of preventative work could mean the difference between a huge vet bill and sick horse or a little salt paste followed by a quiet evening with your favorite, now-hydrated equine. 

This article was originally published in the June 1, 2018 issue of Quarter Horse News