Yikes! Are Those Worms in my Horse's Poop?

Yikes! Are Those Worms in my Horse's Poop?

Finding worms in horse poop isn't one of the fun parts of life with horses. Learn how a targeted deworming program can help minimize internal parasites.

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If you're like most horse owners, you've probably spent more than a few hours of your life cleaning stalls. It's not really a bad job, right? A wheelbarrow, a manure fork and a barn radio playing your favorite music—what's not to like? And most of the time, cleaning a stall isn't a big deal. But while you're singing along, you might want to keep an eye on the manure you're pitching into that bucket. Why? The appearance of your horse's manure is a good indicator of what's happening in his body. While it's not a vital sign like respiration or heart rate, manure can be a guidepost that points towards your horse's digestive health. And one important sign to look for is the presence of worms in your horse's poop. In many cases, you'll never see a thing, but if you notice worms in your horse's manure, it may indicate a problem.

What to do when you see worms in horse poop

A more formal term for equine worms is parasites—specifically, internal parasites, since at least part of their life-cycle occurs within your horse as opposed to an external parasite, like a flea or tick). Most of the time, it's the parasite's eggs that pass with manure in a process called shedding. You can't see them because the eggs are too small. But occasionally, you may see internal parasites in the adult or larva form that have worked their way through your horse's digestive system and into the manure.

If you see worms in horse poop, it may indicate your horse's parasite numbers are elevated, especially if the horse hasn't been dewormed in some time. While it doesn't always mean parasite numbers are high, visible parasites in the manure should be investigated and not ignored. If you see worms in horse poop, you may be looking at one of a few common equine parasite species:

Parasite       Looks like...
Large strongyles  Red or pale, thin and short
Small strongyles      Red or pale, very thin and very short
Equine Botflies (the larva stage)  Reddish and grublike
Pinworms Slightly green, tapered
Tapeworms Pink/pale, wide
Large roundworms Light yellow and very long

Luckily, you have many options, as horse owners and equine veterinarians have dealt with parasite problems successfully for decades. Your best goal is a targeted deworming program you construct with the aid of your veterinarian. Your vet can get to the bottom of your horse's specific parasite problem, usually with a fecal egg test, and advise you on the ideal product for your specific situation.

When you see worms after deworming

There is one time where it might be entirely normal to observe worms in horse poop, and that's for a day or two after a routine deworming. Equine dewormers aim to eliminate parasites in the adult or larva stage, so the appearance of worms in the manure is just an indication the drug did its job correctly.

Watch for false alarms

If your horse's manure has been on the ground for a while—like outdoors in the paddock—you might see something that looks like larvae in the manure. Surprise! It just might be larvae of some kind, like fly maggots or other similar grub. There's likely no problem here; the adult versions of these insects simply laid eggs on your horse's manure after it was already laying in the pasture and are completely harmless. Though, you might want to clean up those piles more quickly in the future.) You might also see earthworms or similar creatures working in the manure to break it down.

But wait—it's not the whole story

It's important to be on a targeted deworming plan and work with your veterinarian even if you don't see worms in your horse's poop. The absence of visible worms doesn't mean your horse is home free. He may still harbor substantial parasite numbers, even if you don't see them.

How can worms affect my Quarter Horse?

The small populations of controlled parasites present in every horse may not cause any problems. But unchecked parasite populations can affect your Quarter Horse's performance and quality of life. Depending on the type of worm, your horse might display symptoms including:

  • Lethargy

  • Poor coat condition

  • Weight loss

  • Coughing

  • Colic symptoms

  • Itchiness

How do I know when to deworm a Quarter Horse?

In the past, many horses were kept on a fixed deworming schedule that rotated among several chemical classes of dewormers to try to keep all parasite loads to a minimum. The problem is that a certain percentage of worms tended to be naturally resistant to the drug, so it didn't affect them. Those parasites would survive the deworming treatment, then produce new parasites with resistant genetics, exacerbating the problem.

In light of drug-resistant parasites, a targeted deworming program is likely your best option. Your Quarter Horse's veterinarian can take fecal samples and use them to determine the exact parasite species present on your farm and help you select the right Farnam deworming product for your situation. IverCare (ivermectin paste) 1.87% is good to use on a horse that weighs up to 1,500 pounds, plus it comes in a Sure-Grip syringe and a red apple flavor that's tasty for your horse. If you have a horse that's difficult to catch or paste, try the FenCare Safe-Guard TypeB Medicated Feed. The PyrantelCare Daily Dewormer 2.11% (pyrantel tartrate) is used as a top dressing on your horse's feed and provides continuous protection. These types of deworming products can help reduce the parasite-resistance problem. If you live where the winters are cold, you might talk to your veterinarian about the value of deworming prior to winter.

It's never fun to find worms in horse poop, but, like a hoof or mane that needs trimming, keeping an eye on your horse's digestive and parasite health is just another chore that comes along with owning a horse. If you follow your veterinarian's advice on fecal tests and targeted deworming, you'll likely minimize the number of parasites in your horse and keep your horse healthy.