09/19/2026
Small Strongyles in Horses:
These are very common parasites in horses and cause a lot of problems! You will not routinely see these worms in your horse's stools, so visual inspection of the p**p is not an indicator of infestation! The best way to see if small strongyles are present is to mix some of the f***s with saturated salt solution, let the worms float to the top, then look at the "float" under the microscope. Generally, floats are pretty good indicator of the mature, egg-laying, worm population present in the horse's intestine.
When horses graze, they will consume the hatched eggs (larvae) that are present on the grass blades. Once ingested, the baby worms travel to the intestinal lining and latch on to the intestinal lining and start sucking blood and nutrients from the intestinal wall. A small number of worms is not bad, but when there is a large number of worms attached to the intestinal wall, clinical signs will be present:
*dry and light colored hairs usually appear along the horse's back and topline
*topline muscles decrease
*horse's may have a pot-bellied appearance
*colic symptoms
*weight loss
*random mild lameness
*grumpy, angry, deppresed, or erratic behavior
*back pain
*resistance to riding, saddling, or training
*increased infections
Treatment: each animal should be treated independently. F***l exams are not fool-proof, but they do help to identify heavy shedders and dewormer resistance. Strongyles are becoming increasingly resistant to chemical de-wormers (fenbendazole, pyrantel, ivermectin, moxidectin).
Pasture rotation, high quality nutrition, dental health, identifying horses with heavy infestation, and keeping horses happy and engaged will help the horse's immune system work better at slowing strongyles. There are also a wide variety of herbs, supplements, and even a fungal feed-through (Bio-Worma) that can help reduce the worm burden. - Dr. Fowler