Six Problems That Can Be Due To Worms

By John Byrd, DVM Problem #2  Wormy Horse Syndrome:  Weight Loss, Diarrhea, Stunting, Poor Hair Coat, Depression, Poor Appetite, and Potbelly appearance  I have elected to discuss all these problems together because they all appear to occur together.  The problems are generally seen in young horses less than 2 years of age.  They are most often… Read more »

Six Problems That Can Be Due To Worms

By John Byrd, DWM Problem #1:  Colic Colic just means a horse has pain in its abdomen.  There are many causes of this pain and different worms can cause colic.  Round worms can cause the pain when a young horse, such as a weanling or yearling, is heavily infected with adult round worms.  These young horses seem… Read more »

The Importance of Performing Fecal Egg Counts on Your Horse

Below is a link to an informative article on the importance of performing fecal egg counts on your horse written by Dr. Craig Reinemeyer.  Occasionally I refer to “Equine Parasite Control”, the book he wrote with Dr. Martin K. Nielson because Dr. Craig Reinemeyer is dedicated to improving horses’ health through parasite research.  Dr. Reinemeyer… Read more »

Why should horse owners have fecal egg counts performed on their horses?

To help slow resistance development of dewormers. To determine how effective their horses’ worm control program is working. To determine what worms are active in their horses’ environment. To determine which deworming medications work best for their horses, To determine which horses are low, medium and high contaminators (shedders of eggs) of their pastures. To… Read more »

Why should you do Fecal Egg Counts on your Horse?

By John Byrd, DVM How do you know my horse has worms?  How do you know you got rid of the worms my horse had?  These two questions were commonly asked when I dewormed horses as a general equine veterinarian.  My standard response was that the drug companies tell us they work.  When the daily dewormers came… Read more »


Recently one of our clients at Horsemen’s Laboratory asked about the accuracy of our testing methods. Horsemen’s Laboratory was established in 1991 and since then we have tested over 66,000 samples. In addition, we have sent samples to the University of Illinois, School of Veterinary Medicine Department of Parasitology and to East Tennessee Clinical Research,… Read more »


A client recently asked, “How effective is Diatomaceous Earth as an agent to prevent or control worms in horses?” Here’s what Horsemen’s Laboratory has found through performing fecal egg counts on horses that are being fed Diatomaceous Earth. In horses that are high shedders, the egg count is often fairly high, 500 strongyle eggs/gm of… Read more »

Review of the Biology and Control of Oxyuris equi (pinworms)

This is a summary of an article that was written by Dr. C. R. Reinemeyer and Dr. M. K. Nielsen and was published in EQUINE VETERINARY EDUCATION.  This article reviews essential features of the biology, epidemiology, pathology, diagnosis, and control of Oxyuris equi (pinworm) infections, and describes the current status of recent biological adaptations.  You… Read more »

Re-Evaluate Your Deworming Protocols This Fall

by Dr. Kenton Morgan, senior veterinarian, Equine Technical Services, ZoetisWhen did you last deworm your horse? What parasites did you deworm your horse against? If you’re not sure, it may be time to re-examine how you approach your equine deworming program. Deworming every horse every couple of months was common practice for more than 40… Read more »

The Ten Commandments of Equine Parasite Control

Dr. Craig R. Reinemeyer and Dr. Martin Nielsen have come up with the 10 Commandments of Equine Parasite Control.  Many of these “commandments” seem counter to what I learned when I was in Veterinary School so long ago.  However, since the problem of worm resistance has remained a concern a new approach must be taken… Read more »