Are You Up To Date on Targeted Horse Worm Control


By Nikki Alvin-Smith


Horse deworming is a necessary part of responsible horse ownership and most horse folks have a protocol in place to manage their horse’s health and protect against the array of equine internal parasites that horses can harbor.


Thankfully in the 1970’s and 1980’s the advent of the simple paste dewormer product, Ivermectin, revolutionized the world of equine worm control and was extremely effective in treatment of bots, large and small strongyles, ascarids and the other nematodes that worm their way around our horse pastures and are laid on our horses’ glossy coats by flies.


When resistance to dewormers began to appear, we were all advised to implement a new program, the rotational rationale. So we blindly began administering different types of dewormers (hopefully not by brand name but by type of effective ingredient), through the myriad of present day pastes on the market on a 6-8 week basis. This random deworming schedule took no account of what worm eggs our horses were actually shedding or how many. The approach was untargeted and this overmedication has caused ever more worm resistance to present day equine deworming products.


Your tack room is probably stocked with an array of deworming pastes. I confess that is the case in my cupboards, and that the Google Calendar pop up reminder was my mode of operation. Which was silly really, because when I think back to my life as a horse crazy kid growing up in England, we never dewormed our ponies without an equine fecal worm egg count completed under the microscope by the neighborhood vet twice a year and administered select worm powders strictly on their advice.


While I realize that we still need to deworm our horses in Spring and Fall to protect them from tape worms and bots, my over-use of dewormers has probably done its fair share of damage to the efficacy of paste dewormers as a whole. Of course, unless I complete fecal worm egg count tests ( F.E.C.T.) on my horse herd, I have no idea if any of my horses harbor worms at all, if any of them are classified as high shedders or if any of them are shedding worm eggs which will infect the pasture with parasites resistant to dewormers. My blind program has probably also cost me unwarranted product expense and caused my horses’ unnecessary stress and exposure to the chemicals contained in those products.


I don’t want to call my vet out every time I want to test or repeat test my horses’ worm egg counts. That would be expensive. But I do want to have a vet’s expertise available to me directly, on the phone or via email, when I need treatment advice or have a question about how to analyze a report. It’s even better if that vet is an expert in equine parasitology.


So my advice is to choose a lab that will not only send you out simple test kits to take your own horse herd manure samples and mail in for testing and provide accurate reports, but also offers a one on one consult directly with a vet. A good lab service will also send you out reminders for re-testing based on the individual horse’s previous results and for busy trainers like myself, an automatic system of replenishment for sampling kits in my barn.


The access to a qualified veterinarian, is especially important when I complete a follow up test to check a horse that has shown a worm egg count that required and has received the necessary targeted wormer product treatment, and the second test reveals a high count or a resistance in that horse’s parasites to the dewormer. Given that my horse didn’t spit out the dewormer and that he received the correct dose, the worm egg count test is truly the only way to know whether my equine worm control program is on target.


As a responsible horse owner I am happy to follow the recent medical advice from veterinary professionals on how to effectively control horse parasites and to conduct fecal worm egg count tests on my horse herd. Are you contributing to the equine dewormer worm resistance issue or are you part of the solution? It’s important, because what we were doing with a rotational dewormer program is not sustainable and there are no new products on the horizon according to equine parasitology experts.