As the spring soil warms up, so does parasitic activity. Small strongyles are currently the most active threat to horses of all ages because the use of ivermectin dewormer has nearly eliminated the large strongyles in most areas. Increased turnout time on pastures also means increased exposure to parasites for your horse.
Small Strongyles Thrive in Spring
Warmer temperatures between 45–85ºF and the moist lush grass of spring are ideal for:
- strongyle eggs to hatch
- larvae to rapidly develop in about seven days into the infective stage when they are covered with a protective coating that allows them to pass through the stomach of the horse without being digested
- extending the life of the larval stages. A drop of dew taken from a blade of grass in a pasture may contain as many as 100 infective small strongyle larvae.
Why Do a Fecal Egg Count?
Once eaten by the horse, the larvae pass directly into the large intestine, where they encyst into the intestinal wall. An adult female small strongyle, emerging from the encysted stage, lays eggs almost constantly. As a result, the worm egg count will be fairly uniform throughout the fecal sample, giving an approximate indication of how heavily your horse is infected. Additionally, the prolific nature of strongyles has allowed them to withstand the effects of deworming medications.
A fecal egg count can provide a baseline for comparison if it is done before deworming and again after deworming a horse that has a positive sample.
Order your kit for a fecal egg count to check for small strongyles--visit www.horsemenslab.com or call 800-544-0599. Read Horsemen’s Laboratory archived newsletter to learn more about strongyles. Horsemen’s Laboratory owner Dr. John Byrd has extensive experience with racing and breeding horses and maintains Westbrook Boarding Stable. He created Horsemen's Laboratory in 1992 so that horse owners could better evaluate their worm control programs and make informed decisions about deworming their horses.