Deworming Information and Recommendations 

New research is constantly coming out on parasitology and deworming in large animals. This information has changed some of the recommendations we are making and may differ from what you have heard in the past. Rotational deworming (giving different dewormers every 1 to 4 months) was used to prevent serious disease from parasites. Unfortunately, this has led to significant parasite resistance over the years. To combat this issue, we have been minimizing our dewormer use based off of fecal tests. A fecal egg count will if your animal is shedding a low, moderate, or high amount of parasite eggs. Experts have determined, however, that this does not necessarily correlate with the actual worm burden inside the gut. 

 Recently, gastrointestinal and skin diseases caused by parasites are making an appearance again with less frequent deworming. To find a balance, we will be using the following general guidelines to maximize prevention of disease and minimize resistance to dewormers on your farm.  Horses, mules, and donkeys should be dewormed at least once a year, regardless of fecal egg count.  Each fall/winter, after the first good frost, a dewormer containing praziquantel should be given to treat for tapeworms, which don’t usually show up on a fecal. Praziquantel is combined with either Ivermectin or Moxidectin – examples include Zimectrin Gold, Equimax, and Quest Plus. A fecal sample should be tested in the spring or early summer to determine your horse’s shedding status. Horses shedding a moderate to high load of eggs will require more frequent deworming to decrease pasture contamination.  We can check for dewormer resistance on your farm by rechecking a fecal egg count 10 to 14 days after deworming.  As with many things, one size does not fit all – recommendations may differ based on your horse’s medical conditions, age, housing environment, and lifestyle. Foals, weanlings, and yearlings have different requirements than adults. Please consult with one of our veterinarians at your next appointment to determine the best plan for your animals.