What You Need to Know about Equine Parasites
Parasites. The word sends chills down your spine, doesn’t it?
No one likes to think about worms taking up residence inside their horse, but the fact of the matter is that they do. For many years, the goal has been to completely eradicate them in our horses, which has ultimately led to widespread dewormer resistance. Essentially, the worms have learned to adapt and many have become immune to certain chemical dewormers. It’s enough to make a horse owner want to panic.
But what if I told you that parasites aren’t necessarily the enemy? You might think I’m crazy, but hear me out–a few worms aren’t going to cause a problem for your horse. In fact, studies have shown that wild horses are also affected by parasites, but the levels rarely reach a high enough number to create serious health issues. The real enemy is abnormally high levels of parasites, which are created by confinement.
Horses in confined spaces are prone to parasite buildup simply because they are grazing or eating around manure where parasite eggs have been shed. Re-infestation occurs and if no intervention is made, the numbers will increase. Not surprisingly, a large worm burden can negatively affect your horse’s health.
Our goal should not be to completely eradicate parasites, but maintain a low level of infestation.
For a number of years, it was recommended that horse owners rotate the class of dewormer and administer every three months, and being the conscientious horse owner I am, this is what I did religiously for years. Now, researchers know this method is not only ineffective but further expanding the problem of parasite resistance. If you’re still blindly giving a chemical dewormer every few months, please stop!
As this article from Holistic Horse so wisely states:
In nature, parasites do not like to kill their hosts as it deprives them of a place to live. When horses are confined and crowded with others of the same species, the intestinal immune system is stressed and parasites can become a life-threatening problem. However, current literature is emphasizing that parasites are seldom the cause of serious clinical disease except in extreme situations. It is not necessary to maintain a zero fecal egg count.
With that said, here are some important things to know about equine parasites:
Fecal Egg Counts
The most important thing we can do is use fecal egg counts (FEC’s). These can be done to determine if a dewormer is needed–and also to tell if your deworming methods are working. You can have your vet do the counts or you can even purchase a microscope and FEC kit and learn to do them yourself. This is what I’ve been doing for the past few years. In fact, I just did FEC’s on two of my horses earlier this week and found only one small strongyle egg in one sample and just a handful in the other. Both are considered very low counts. I will do them again further into spring when the grass is completely in.
But depending on what type of eggs, larva, or worms are present, FEC’s will help you determine your plan of action since different dewormers target different types of parasites.
Pasture Management
Pasture management is a crucial part of parasite control. Eggs are shed in the manure and when horses eat near piles of manure, they will inevitably consume larva. If we rotate pastures, use multi-species grazing, or pick up manure in the pasture, however, we can make a big difference in their level of re-infestation. I’m fortunate enough to have plenty of space and three pastures to rotate my horses on, but I’ve also picked up manure in the past as well. If your pastures are overcrowded, this will be much more difficult, if not impossible to do, so it’s important to only keep the number of horses your facilities can accommodate.
Natural Parasite Control
There are several herbal and “natural” alternatives for parasite control, but most are just that: control. While there are a few herbs that are said to rid the body of parasites, some can be controversial (such as black walnut). I don’t feel qualified enough to comment on their use or efficacy. However, I do believe that many herbs support a healthy immune system and have anti-parasitic effects. In other words, they can create an environment where parasites feel less welcome.
Food Grade Diatomaceous Earth is also controversial for some, but I have been using it on and off for over a year now and my FEC’s have stayed low. Coincidence? I don’t know, but I plan to continue using it unless I’m given a reason not to.
Garlic is also known to have anti-parasitic effects. In large amounts, it is not safe for horses, but many feed a small amount on a continual basis or at specific times (such as during the full moon cycle) and have had reported success.
I’ve also written about other forms of natural deworming, such as in this article on a study using micronized coconut and onion.
There are alternative forms of parasite control that have proven successful, and in some cases (especially in drier climates) they might be all that is needed. The key is to use FEC’s to ensure they’re working for your horses. Natural parasite control should also be used in conjunction with pasture and/or manure management.
Support a Healthy Immune System
Just as bacteria and viruses pose a significantly lower threat to animals with healthy immune systems, so do parasites. It’s much easier to start from scratch and build a healthy horse than to take an unhealthy horse and turn things around, but that’s not to say it can’t be done. Nutrition, environment, and stress all play major factors in the health of the immune system, and I wholeheartedly believe you can prevent high levels of parasites simply by supporting a healthy immune system.
Interestingly enough, if allowed to do so, the young horse’s immune system learns to naturally defend itself form parasitic invaders. This is called acquired immunity. If we’re constantly deworming young horses and striving for a zero egg count, they won’t develop acquired immunity though. Also quite interesting was an LSU study where horses were subjected to intensive deworming regimens for one year. The following year, researchers discovered those horses were more susceptible to parasitic invasion. Exposure to parasites creates natural immunity. The key is to not let the parasites get the upper hand though.
Of course, I would never advocate for anyone to stick their head in the sand, not deworm their horse, and hope for the best. But we must use common sense and stay updated on current research regarding equine parasites. Don’t let fear keep you in the old pattern of blindly deworming every few months. Use fecal egg counts and pasture management, support your horse’s immune system, and possibly employ some natural methods of parasite control, and hopefully you won’t have to rely on chemical dewormers nearly as much.
Ta-ta,
Casie
Sources and Further Reading
Hi Casie…Every time I read articles about parasites it seems very few mention the parasites that don’t show up on fecal egg counts. One of the horses I share life with almost always has a low to no fecal egg count so there should be no need for wormer …right? But every year ( if I don’t worm him with poison) he gets a summer sore in the corner of his mouth from Bot fly larvae that does not show up on fecal egg counts. The other two horses I share life with get Neck Thread worms…and these don’t show up either. I also think there are a few more …tape worms? I am a person who hates poison so would love to never worm again. The fact is though that many parasites do not show up on fecal egg counts and this really needs to be included in articles about parasites so that everyone can be better informed. I will also be learning to do my own fecal counts this year as I have recently been told that mail in fecal counts can not be relied on? I am no expert just a backyard horse girl who wants the best for the horses. Please elloborate if any of this is wrong.
I just want to learn all I can✌❤️
Hi Michelle, you are right in saying not all worms show up on FEC’s. They are a guide for deworming, but not completely foolproof. If other symptoms of high parasite levels are present, I wouldn’t hesitate to deworm. Tapeworms do not typically show up on fecals either, so if you live in a region where they are known to be a problem (or suspect them because of symptoms), I’d definitely deworm for those too. My main concern is people using chemical dewormers blindly (and way too often), thinking they’re doing the right thing, when in fact, they’re just adding to the resistance problem. We need to be smart about deworming, and it sounds like you definitely are.
As far as the mail-in FEC’s, I don’t know about those. I’d rather just do them myself. It’s not hard if you have the right equipment.
My rescue filly was absolutely infested when we brought her home, she was also terrified and unhandled so paste worming wasn’t really an option. We tried the pellet chemical products, but soon switched to an herbal that I have just kept them on monthly. I am going to order the kit you recommend, as I just like learning to do stuff like that anyway, but that way I can keep up on it for the horses and goats. Plus that kit costs about as much as our vet charges for 1 horse so that makes it totally worth it
Hi, I was reading recently about how the old Cowboys deformed with chewing tobacco. Wondered if you’ve ever heard of this? I haven’t tried it, but wonder if it might be an alternative to the chemicals?
Hi Cindy, I have heard of it, but I’m afraid I don’t know much about how well it works. Maybe someone else will chime in here.
I’ve been doing my own counts for a couple months now for my horses, and wondering if you have any information on doing fecal counts for dogs/cats/other animals.. Are the same types of eggs present? I presume you do the test the same way, but just wondering if the results are dramatically different. Thought I’d ask around on here before taking it to my vet!
Hi Fiona–great question. I don’t really have any info on smaller animals (mainly write about horse health), but I’m sure doing the FEC’s is feasible. The eggs will probably be somewhat different, but the process should be the same (just smellier!)