A Better Approach To Parasite Control

From an email to me:

Hi Dr. Tucker,

Yes, I wonder about your recommendations per worming horses. It is springtime. I would think worming will change the pH of the stomach, so want some input as to how to proceed. Thanks.

My response:

Life is always a balance between what should be normal and the addition of anything that would change this balance. This includes food, medicine, stress and environmental factors. A normal immune system will take care of intestinal parasites if the system is not overwhelmed. But in today’s world with confinement for our horses, most horses eat where they defecate.

The best solution for parasite control is to clean up the manure from where they eat. This requires picking up the piles in the paddock either by fork or by vacuum at least every 3 days.

Manure is picked up daily in the paddock the old-fashioned way.

Removing all grain and grain/plant byproducts from the horse’s life and adding protein with a full spectrum of amino acids to restore the health of the immune system are both additional steps in controlling parasites.

But right now, with the increasing daylight of spring, any encysted larvae will be coming out of winter mode and shedding eggs. If your horse has any egg count in a fecal test, deworm once a week for 3 weeks with ivermectin. Kill the little monsters. Don’t worry about the gut pH or inflammation. The battle must be won. Then commit to building the immune system and cleaning the environment.

A word about fecal egg counts. Let’s say your horse tests at 100 eggs per gram. 1 gram times 454 = 1 pound so 454 times 100 eggs per gram = 45,400 eggs per pound of poop. This is why I say “any” eggs in the test are worth treating.

Treat the infection first and then restore the health of the gut because the damage from intestinal parasites is as important as all other causes of gut inflammation. The real problem comes from cleaning the environment which needs to be done AT LEAST every 3 days. The egg that sheds in the feces takes 3 days to develop into larvae that can infect the horse. Every other day is a good protocol to reduce the contamination in your paddock.

In the wild, horses defecated here then walked far away till the next defecation. In a week they would be 100 miles from their first pile. Some say that deworming medications are not natural but then you can also say fences are not natural either.

One last thing. Did you know that ivermectin (Eqvalan and others) and parental tartrate (Strongid and others) are approved for use in humans (image below)? Yes, humans get intestinal parasites too. But we don’t eat where we defecate since toilets were invented not too long ago. We also use knives and forks, the best anti-parasite invention ever created along with soap and toilet paper.

Pyrantel Pamoate is the ingredient of liquid Strongid for horses and dogs. This was found on the shelf at my local Walgreens pharmacy store.

In the gallery: pictures of manure vacuums for cleaning up the pastures and one farm’s approach to manure control.

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  1. Hi
    Thank you for this excellent website. I pretty much follow everything you outline, however, I feed Hemp hulls and oats where needed, to all my horses. Thoughts?

    1. Hulls are removed from grains and seeds because they cause inflammation in the guts of humans. Rather than throw out these byproducts, companies are adding them to horse feeds.

      I used to feed oats to our horses in the 1970’s. If a horse needs extra carbohydrates then adding a clean oat (hulls removed) then oats will work well. But when carbohydrates are added in excess of needs then insulin spokes and metabolic syndrome occurs. More on the new website soon – TheHorsesAdvocate.com

  2. I am so thankful to come across this website/blog. I hope you can help me. Two years ago we adopted 3 wild mustang mares from a failed sanctuary in S.Dakota. These girls are 20+ years old. Shortly after they were here I took in stool samples to my vet. They came back ‘horrific’. I gave them ivermectin paste on their feed. My only option as they were unhandled. Tested again last fall and still bad so I did the 5 day Panacur treatment. Ivermectin again in the spring. Tested again this fall to see if any progress but still came back heavily infested. Someone suggested Quest Plus. But an online vet said putting paste on their feed is ineffective 😳. So I called the company Zoetis and spoke to their vet and he said not to give it to them since they are under weight and heavily infested. He recommend StrongidC 2x. They just finished 3 weeks of that. I’m ready to test again. If they are still infested I don’t know what else to do to help them. I did buy a pasture vacuum last year and try to keep their area very clean.

    On the other hand I am very interested in your no grain program. These girls never had grain before I had them. Every few months I try a different recommendation of grain from senior feed to beet pulp pellets etc., trying to put weight on them. Nothing is really working. Right now they are getting Triple Crown Senior, 5 lbs divided into two feedings. They have hay 24/7. I am so desperate for help for them. I want them to fill out and be healthy and live there lives out healthy. My vet won’t come out because they are not handable. He will answer some questions via messenger on Facebook. I am having to depend on what information I can get online. I have gentled them to a degree. Can halter two of them now and working on leading. One girl continues to heave off and on constantly 😔

    Sorry so long. Just need help. Appreciate any you can give!

    1. They sound like they are protein deficient (I have plenty of info on this here). Protein is needed for the immune system to function as well as restoring the health of the gut bacteria where the vitamins are made.

      Strongid-C is a great product but I haven’t seen it work in an overwhelming infection. Cleaning the environment is the primary treatment (vacuum the paddock every other day and daily cleaning of the stall). The immune system can then work once the environment is cleaned and the protein (amino acids) are restored.

      1 pound of soybean meal per 1200 pounds per day. You can double this to start with. If they don’t like it be patient. Add it slowly or add it to something they love like moistened alfalfa cubes.

      Come back here in a few months and tell us how it goes.

  3. Thought I would share a brief recent correspondence with an equine parasitologist that we had sponsored for a presentation some years back. He is one of a few dedicated equine parasitologists that are not associated with a drug company. I do a FEC once a year just because I’m told that it’s important to do. I then get a detailed treatment per horse to follow based on the counts and type of parasite found. The results back started a discussion between my husband and me so I reached out to see if anything had changed on the worming front since our last contact.

    I asked “So has there been any more studies establishing that the level of the shed in a horse is directly related to the actual load of that parasite in the horse? I remember that at the point of your visit, the FEC that we use did not establish that the horse actually carried a low, medium or high parasite load but rather established that it was a low, medium or high shedder for reasons that were not quite understood. The test was basically to determine the presence of the type of parasite and the targeted treatment. Correct?
    Has it been established that a previously documented high shedder is more likely to have secondary health problems as opposed to a medium or low shedder?”
    His response “It has long been established that there is no correlation between egg count and worm burden. Similarly, egg counts have not been related to clinical manifestations.”

    So what do we do with that? As I read the latest AAEP Parasite Control Guidelines I’m tempted to compare this to your post on human dentistry. Have we all “drank the Kool-Aid?”
    I have little doubt that a compromised horse can succumb to some complications from a parasite. But little evidence is presented to create this whole industry and “healthy protocols” to regularly reduce/eliminate them. I think it’s especially concerning as we continue to learn more about the importance of gut health and how what we do to it affects the body functions. To suggest worming only targets/effects that worm is naive at best. The best advice in the whole 25-page guideline is one that you endorse…….clean up the horses living environment the best you can.

    1. Thank you for sharing this. I have such an interesting perspective due to my longevity in the horse industry. Seeing the advancement from a buccal tea enema for pinworms to the latest theory of Fecal Egg Count (FEC) driven treatments I can obviously see the holes in the theories. What about nutrition, immune system health and gut health? What about environmental cleanliness? To me it is obvious and I am glad that you and your husband can also see it. Love the “Kool-aid” comment – and for those of you too young to remember, a cult leader murdered all of his following in the Johnstown massacre when he convinced them all to drink poisoned Kool Aid. In essence we all will swallow what we are given if we all believe what we are told.

    1. This only spreads the manure out so that the parasites are spread out. Only desiccation (dry heat) kills parasites so if you have dew or rain they will survive. Much better to pick them up or vacuum.

      1. I am in high desert Colorado (eastern plains). It’s quite dry and sandy. I use a Newerspreader on a vacant pasture. If it dries over summer, is that sufficient? I am trying to rebuild the pastures from weeds and cheat grass by fertilizing and mowing. How long does it need to dry? I have been spreading over the winter in one 10 acre field that they are locked out of. So, there’s been some snow and there will be spring rain. July & August is typically 90s-100s and dry.

        1. I have been told that the only thing that kills parasites are “long periods of dry heat.” However no one has defined “long” or “dry heat.” I do know that most internal parasites survive winter cold. I also know that if there is grass there is moisture.

          An alternative plan would be to compost the manure as the heat there will kill the parasites. I have been told that spreading composted manure is OK.

          I have not seen or heard any studies about how to effectively kill parasites in the manure before spreading that has good data – only hearsay. My thought is to somehow dry or heat (or both) the manure but avoid spreading fresh manure onto an active field where horses graze. Use a commercial fertilizer rather than horse manure as a fertilizer. And of course keep the horses as healthy as possible so they can fight off any parasite with their healthy immune system.

  4. Thank you, Doc T, for the information! A learning experience as always!! I recently brought home two horses from different locations; both had been kept in filthy pens steeped in dried & wet manure, dirty water, hay fed on the dirty ground, one was kept in a pen with about 20 other horses. I keep my place “immaculate” – picking up manure 2-3 times a day. I did fecal tests on the horses and both came back with Strongyles (100 & 150). The lab I use said if count is less than 200, retest in 3 months, so I didn’t worm them. After reading your article, I’m wondering if I should go ahead and worm now as you suggested. My other thought is to retest in one month and see if my clean horse quarters and “natural horsekeeping” practices solve the problem. My horses have grass hay 24/7, clean water 24/7, no grain, live together in their little herd of two, are not confined in stalls, and are encouraged to move (via water tanks and hay placement around the small property they live on).

    1. I would retest before treating. I believe in the immune system and with your clean environment and improved nutrition, I’ll bet that not only will they be negative but you will also be able to correlate the test to an improved hair coat and brighter eye.

      However I would add soy bean meal to their diet as this will help to restore their immune system quickly.

      Please come back here and post the test results and your observations.

      1. Reporting back! My clean environment helped one horse but not the other.

        The 15 yo QH mare, who was kept (separately) in a filthy pen before I bought her, initially tested positive for Strongyles – 100 eggs/qm. Five weeks later she tested Negative Stool. Yay!

        The 4-1/2 yo BLM mustang gelding who was kept in another location in a filthy pen with many, many horses (mostly BLM mustangs fresh out of the even filthier holding pens) initially tested positive for Strongyles – 150 eggs/qm. Five weeks later, no change. I was surprised that he didn’t improve at all and am wondering if the parasitic load was just too much for him – even though he’s been in my ultra clean environment for five weeks now. Debating whether to worm now or give him more time – thinking worming now is the better option.

        1. Parasite control starts with the horse’s immune system. A clean pasture is great but when the immune system is compromised then the horse cannot fight the infection it already has. Note the egg count did not rise. Deworming and adding protein to the diet is the recipe for helping this horse. Protein of course will help them both recover their lost muscling.

          1. Thanks. Makes sense.

            I started the mare on SBM a couple of weeks ago because she’s lost some muscle (mostly due to lack of exercise as I’ve been out of town). The SBM hasn’t helped her (am feeding about one pound a day) so may have to up the amount.

            The gelding with the parasites has good muscling, a great topline and is getting fat from eating so much, so I haven’t put him on SBM yet.

            It’s hard bringing horses to a natural environment when they’ve been used to being confined and getting one flake of hay in the morning/one in the afternoon. They are free-fed here, not stalled, and have access to hay 24/7 so it takes awhile for them to learn that they don’t have to eat everything in sight as they will always have hay. And clean water. And shade.

            If you have a recommendation for a gentle dewormer for my gelding that would be great – am thinking of SafeGuard (have used it before on older horses with no problem). I don’t like using the toxic dewormers but the gelding is young and a former wild horse, so he should not have any problems. I hope!

          2. SBM provides the broad variety of all the essential amino acids needed to rebuild all the things made of protein. For the top line, this rebuilding process takes from 4 to 6 months, not a couple of weeks. However the abdominal muscles often tighten up in 2 to 4 weeks losing the hay belly in that time frame.

            The gelding with the fat but also with the egg count epitomizes a horse without enough protein. It is hard to see a top line in a fattened horse. The increase in body fat is evidence that there is gut inflammation and the sugar in the diet (grass and hay included) is being converted into body fat. This process adds to the chronic protein deficiency of horses and the evidence for the low protein is the poor immune response to the parasites. This is the causes of the continued positive egg count. This horse needs the soybean meal to correct this. Remember that the immune system is almost all protein. For more information on this read my blogs on nutrition.

            There is no “gentle” parasite medicine nor are there any more “toxic” than others (the exception are the organophosphates which are hard to come by these days). You need an effective medicine and a protocol that works. Talk with your vet on this but I have no problems giving ivermectin. It is very safe. The parasite load is damaging the horse and this needs to be weighed against giving any medication. But if you are concerned then add the SBM and wait 2 to 4 weeks and recheck the egg count.

  5. I’m not a doctor but I’ve read some people who have a lyme infection take ivermectin to kill the spirochete and have reported feeling so much better. I may try it myself someday as my Infection wasn’t killed off with the 24 day course of doxy. Great article as usual, thank you.

    1. There is a physician in CT who has identified 25 genes that have a pattern of on / off that occurs with a Lyme infection. He also identified the same 25 genes with a different on / off pattern that SHOW Lyme disease but is not. And guess what? The activation of these genes are associated with wheat. He now treats people unresponsive to Lyme therapy with diet and this is showing great results.

      I just looked for the podcast where I heard this. It is within the past 4 months – really cutting edge stuff where the first public testing for the gene sequencing is being done starting this past February. But I can’t fine it nor can I Google search for it. But keep a eye out for this as I’m sure we will be hearing more about it. Or you can cut out grain from your diet….

  6. Hi Doc T, it’s me Hope again, many thanks for your last message. This new blog reminded me, sadly, of losing my nice litle black mare, Sadie, to blood worms. I still want to understand how this happened in a barn with a worming program. Are blood worms unlike all others? Treated differently? How I can I learn more? I realize I’m asking for more than my share of answers, but perhaps others will be interested as well. If and when you have time. And thanks.

    1. Sorry about the loss of Sadie. Unfortunately “deworming programs” are usually ineffective as deworming every 6 to 8 weeks is based on a model showing that a significant amount of eggs would be present in the feces at that time. At that interval horse owners would deworm and “see” an improvement or even parasites coming out in the feces and this would justify the contimnued purchasing of these chemicals. Sadly this is actually true. The study was very well done and reproducible. While it showed that there would be a treatable load in 6 to 8 weeks in a paddock densely filled with horses (as most boarding barns are), it also CLEARLY showed that a paddock vacuumed of fecal piles resulted in the immune system of the horse destroying all internal parasites with a zero egg count. But that didn’t sell deworming medication or indoctrinate horse owners and barns into believing a 6 to 8 week protocol would work.

      All internal parasites should be dealt with by migration of horses to clean paddocks and their immune system. All other “programs” are ineffective for all parasites. In fact it is reasonable to say that parasite problems occur in captive horses (fenced in, dense populations) and not in free horses (or sparse density of 1 horse per 10 acres). This is how they have made it millions of years without the need to deworm them.

    1. I have a client who sent me details of how to turn the intake of a leaf blower into a poop picker. As I re-do TheHorsesAdvocate.com website I will find it and include it there.

  7. I have a herd of 6 horses in Montana where I have the ability to rotate the group to a number of pastures. Is there a time schedule to move them that would naturally safeguard them from parasites? Could I move them, drag their paddock, let things die off before they return to that paddock? (To avoid picking up manure)

    1. Dragging does not help to eliminate infective larvae from the field with the exception of very hot and dry areas. Dry heat desiccates them and they die. Otherwise these larvae and ascarid eggs are very hardy especially where there is moisture. In fact the larvae actually climb up the blade of grass in the morning dew and then descent towards the ground as the dew dries. A rational procedure then would be to turn out horses only after the sun has dried off the dew – but this is impossible in most areas where rain falls.

      Some larvae can last for years and survive winter cold so there is no effective pasture rotation schedule that I know of. Dragging only spreads out the manure. With a little more time invested you could use the machine you drag with to pull a manure vacuum and pick up the piles 2 to 3 times a week.

      In a study I saw years back, horses kept in a clean paddock would defecate in one area keeping the rest of the paddock clean. While you and I know of horses who poop wherever they please, I will agree that an unkept paddock usually ends up being littered with piles while generally paddocks kept clear of piles on a regular basis do seem to have piles more concentrated in the resting or feeding areas and not in the grazing areas.

  8. Geoff:

    While agreeing with everything you say, it’s not quite as simple as keeping paddocks clean, etc. For example, bot flies travel several miles to find new hosts. Then horses end up licking the eggs off their legs & the cycle begins in a new location..

    I suspect many other parasites have similar strategies for ensuring their survival. Thus, modern anthelmintics have their place. The challenge is to use an appropriate rotation to (a) treat the current likely parasite infestation (which is seasonal), and (b) to avoid over-use such that we induce resistance.

    John Hall

    1. I remember in 1974 my vet coming into the barn waving some aluminum foil packets and proclaiming, “We now have medication to get the parasites!” The horses wouldn’t eat it though. Soon after the paste dewormers appeared. All the vets made a LOT of cash by tube (a tube passed up the nose and into the stomach) deworming fields of horses. I made money visiting horses with colic after an overdose of a very toxic dewormer was given – usually on a sunny spring Sunday! And now we are all told that there is resistance and we should not deworm unless there is a significant load (an infection of internal parasites). It is impossible to find anyone saying to clean up the feces and you will clean up the parasites probably because this involves work. As a result, the chemicals are overused or used improperly and thus your assessment here is true. These little buggars do what they can to survive by adapting to the chemicals etc. But I have not seen resistance of parasites to pitch forks! Only resistance from humans to use them.

  9. Hi Doc,

    I read your recommendation regarding worming and have two additional questions. First, do you recommend a fecal test before administering a wormer? Second, I know some horse supplements claim to have lactobacillus in them but I have also read that not all of them actually provide the horse with the beneficial bacteria. Do you have one that works, one with live bacteria, that you recommend? Also, do you know how to replenish bifidobacteria, one of the others that seem to be lacking in horses?


    1. 1) No I do not, but that doesn’t mean you shouldn’t. You need to work with your vet on this. It really depends on the trustworthiness of the testing. In the past a high school student would do fecals on the weekend for experience. Now there are qualified testing labs. Also. what is the definition of a positive. Mine is 1 egg/gram while others it may be as high as 300 epg. If you feel confident then do one before and then after treatment to verify effectiveness. One more thing – increasing and decreasing daylight may have an effect on the egg count as it affects the movement of larvae in and out of the encysted stage.

      2) Probiotic bacteria added to horse feeds is, in my mind, unproven because the feed manufacturer doesn’t usually reveal the source of the ingredient. In may come from a can batched in another country and is not fresh. And even if the ingredient is fresh and effective in the feed, there is little evidence that they survive to the place where they are supposed to live in the gut. Human testing of feces for gut bacteria do not show the bacteria ingested in probiotics (there are some exceptions such as prescription strength probiotics). In my mind, the jury is out on probiotic use. The two camps are those testing for it on one side and the other side are the manufacturers. No one has cultured the horse gut of a freshly killed horse to determine what bacteria are supposed to be in there and where. All there is is fecal testing and I know of one company in Wales that does this. I believe that Life Data here in the US is starting a beta program. The link for Wales is here: https://www.equibiome.org/?fbclid=IwAR1kdzlJEI99SJbFK1GCan1LRJqFU_bacrbloAUDWVi11yNuYTiem1KVc5k

      1. Well, actually we have examined the equine biome at Freedom Health LLC. Much to many experts’ amazement, every horse is different and, while about 7 species predominate, they’re all over the place.

        1. My wife and I tested our own microbiome this year. Hers had a lot of variety but mine had a limited variety. Which is correct? And we eat together half of the year but the other half is on-the-road food. I still don’t know what to make of it.

          As I travel from farm to farm throughout the US I see a huge variety in pasture and hay. On top of this is the genetics of the individual. My broad conclusion is everyone has a different gut microbiome starting at birth. Each can work with what they have until something comes into the gut to start the inflammation. For some horses a balance can be made. For others the inflammation leads to a lot of problems. And over this inflammation is the mitochondrial exhaustion from the carbohydrate dependency. If horses could get a break from the constant sugar intake (no grain plus winter dormant pasture) then the cells and their mitochondria could have a chance to clean up the mess.

          As always John, thanks for your insights and comments here. You are so appreciated.

          1. Geoff:
            You’re probably correct as to the sources of differences, although coprophagia probably plays a major part at the outset. The upshot remains: every single horse is different, just like us humans.

  10. Good info Doc T. Thank you. Would the 5day power pack work just as well? I usually give that once a year after the first frost, or before if I see her scratching her butt on posts, and I know her udders and peritoneal area is clean.

    My husband is in the hospital with a second run of c-diff. I know it would be useful for him to take probiotics. Will it do any good to take them while he’s being treated with the stomach specific antibiotic, vancomycin? I guess it would be less wasteful and more effective after medication routine is complete?

      1. I think there is no solid evidence for the use of probiotics in horses being given antibiotics. I also think that an antibiotic may also kill the bacteria in the probiotic. But there is no downside to giving them either. Maybe if the horse shows signs of gut inflammation during the antibiotic treatment then the treatment would need to be reevaluated.

    1. The frequency of giving the medicine is important. The 5 day treatment has been proven effective in studies done by the company but the once a week for 3 weeks protocol seems to have worked well too. Better than both is cleaning the paddock.

      Frost does not kill parasites. However deworming for bots after frost does work as well as deworming after the first snow as long as the snow stays for a while. The snow is a barrier where the horse cannot ingest the larvae.

      An itching but has often been associated with pinworms but in my experience it is more an irritation of dried feed material just inside the anus. Cleaning out the anus (finger deep within the anus) with water and a wash cloth followed by application of a steroid cream within the anus usually helps these horses. I should do a post on this with more details.

      I cannot offer advice about your husband. There are few probiotics that are not digested by the stomach acid. Please consult your physician for advice on prescription strength probiotics.