Manure Matters

By: Dr. Lydia Gray

Most of you have probably already dewormed your horse for the first time this spring.  Some of you may already be on your second or third deworming.  However, there’s something else you can do to really help protect your horse from parasites, and that’s have a fecal egg count performed.

A fecal egg count measures the number of strongyle eggs your horse is passing in each gram of his manure. When you send a sample to your veterinarian or independent laboratory, you get back a number like 50 EPG (eggs per gram) or 500 EPG. This is called a quantitative test.

When you take a sample of your dog’s stool to your veterinarian, the clinic runs a qualitative test. A technician performs a fecal flotation to look for the presence of roundworms, hookworms and other parasites. You get back an answer like “yes, your dog has roundworms” or “no, your dog does not have hookworms.”

Why the difference? It’s partly because some of the parasites that dogs (and cats) get can also be picked up by people, so we want our smaller companion animals that live with us to be completely parasite-free. But it’s mostly because horses, being grazers, will never be completely free of parasites. We just want to know if they have a high load of parasites and need dewormed to:

1. protect themselves from problems like colic, weight loss and diarrhea and
2. protect the pasture from lots of eggs being passed onto it.

If you can only afford one fecal egg count per year, run it right before deworming your horse for the first time in the spring. If the number is low (less than 200 – 250 EPG), that particular horse has good natural immunity to strongyles and may not need dewormed as frequently. However, if the number is more than 200 –250 EPG, that horse may be a “chronic shedder.”This is a horse who may not show signs of parasitism, but is carrying lots of adult worms that are laying lots of eggs, spreading them all over your pasture to the other horses. Chronic shedders may need dewormed more often than other horses.

If you can afford two fecal egg counts per year, have the second one performed 10 to 14 days after this first deworming. This is called a fecal egg count reduction test and tells you if your dewormer worked. Scientists are discovering more and more resistance to commonly used dewormers so it’s important to make sure there are actually LESS eggs in your horse’s manure AFTER the deworming. You don’t get any points for going through the motions!

About Dr. Lydia Gray