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Hey all,
My name is Michael and I study the effects of the many different populations of bacteria in the stomach of the horse. Without getting into the many details of the project (you are certainly welcome to ask and I will answer!) I am studying how worm infestation affect the horse's health and How anthelminthics affect the horse's health as well.

To further my understanding on how these two factors affect horses I am coming to you with a question today, and i hope to have a good response and be able to count on the experts here for more!:)

What type of drug do you use to eradicate the horses(Ivermectin, Moxidectin, Fenbendazole, Pyrantel Salts) and do you notice any affect on the horses performance when using these drugs?

Any information, suggestions, or questions would be great for my understanding and beneficial to my project!

Thanks
 

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What timing!

I'd love to see the finished paper and I'm willing to bet a lot of people here would.

I have 3 horses. None would I class in anything using the word performance. 2 are in advanced old age and the other in her mid teens and just ridden lightly. They are at very low risk for parasite infestation. They don't come in contact with other horses and are wormed regularly. I rarely even see another horse ride by. They wander 20 acres.

Mostly I use whichever brand of ivermectin is on sale but I do dose with EquiMax, which is ivermectin/praziquantel mixed and occasionally some Pyrantel.
No side effects noted ever. The smallest and oldest one, 40yrs is regularly double dosed because of a neck threadworm issue during the warm weather.
 

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Michael, if you are doing research for a paper I would recommend making use of an online survey setup like survey monkey so that you can gather more detailed information on each horse, product used and alterations in performance (if any). Using a survey also helps to generate your statistical data in usable forms.

Also consider contacting local veterinarians and ask them if they would send home a survey link with horse owners after they deworm their horses. This way you have owners who can specifically look at fecal consistency, appetite, etc after deworming with an eye to being able to report what they see.
The kind vague anecdotal evidence you will get here will be of limited value in a research setting.

That being said:
ivermectin use in 5 horses (ages 9, 11, 15, 19 and 35) produced no changes in performance
moxidectin/praziquantel use in the same 5 horses has produced no changes in performance.
 

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Michael, if you are doing research for a paper I would recommend making use of an online survey setup like survey monkey so that you can gather more detailed information on each horse, product used and alterations in performance (if any). Using a survey also helps to generate your statistical data in usable forms.

Also consider contacting local veterinarians and ask them if they would send home a survey link with horse owners after they deworm their horses. This way you have owners who can specifically look at fecal consistency, appetite, etc after deworming with an eye to being able to report what they see.
The kind vague anecdotal evidence you will get here will be of limited value in a research setting.

That being said:
ivermectin use in 5 horses (ages 9, 11, 15, 19 and 35) produced no changes in performance
moxidectin/praziquantel use in the same 5 horses has produced no changes in performance.
The information I have, is that Ivermectin has been shown that some geographical areas have parasites that have become significantly resistant to Ivermectin
Thus, I use Quest plus, at least once ayear.
I would be surprised that Ivermectin+ praziquantel would be compared to Moxidectin without the prazquantel.
Sorry,, not questioning your stats,but as a human lab tech, having that background and applied it to horses that I have raised, I do deleve into horse based data and research

The past two decades have seen increasing reports of parasite resistance to deworming products...including in our area! We are seeing the most resistance to fenbendazole and ivermectin products. There are no new deworming drugs being developed and it is unlikely that this will change anytime soon. Therefore it is our responsibility to use what options we have prudently to minimize the further development of parasite resistance. This will help us to prevent the recurrence of the terrible diseases parasites caused our horses in the past. Newer deworming protocols aimed at achieving these goals focus on the individual horse.


here is a study that pooled different geographical area data, on efficacy of moxidectin versus Ivermectin

Parasites & Vectors | Full text | Moxidectin: a review of chemistry, pharmacokinetics and use in horses

Quest is also effective against a growing parasite concern, that of encyted small strongles, while Ivermectin is not, so another reason I use Quest
Of course, with growing amount of parasite resistence, and no new class of de-wormers on the horizon, strategic de-worming programs are recommended, based on fecal egg counts of individual horses in a herd
 

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Smilie, yes there are some areas where specific parasites---ascarids--have developed a significant resistance to ivermectin. Ivermectin and moxidectin are currently the two dewormers without significant resistance issues in small strongyles which are the main concern in adult horses. So, for adult horses ivermectin and moxidectin are going to be the two most effective products.
http://lacs.vetmed.ufl.edu/files/2011/12/kaplanparasites.pdf These Ain't Your Father's Parasites: Dewormer Resistance and New Strategies for Parasite Control in Horses. Ray M. Kaplan, DVM, PhD, DEVPC, Department of Infectious Diseases, College of Veterinary
Medicine, University of Georgia, Athens, Georgia

When talking about resistance, you really have to consider what parasites you are talking about resistance in because the main parasites of concern change with the age of the horse and because resistance is seen at different levels to differnent drugs. So, you have to know which parasite is resistant to a given drug and what parasites are likely to be a problem in your horses to know which drugs are or are not likely to be effective. For instance, ivermectin and pyrantel both have issues with resistance in ascarids which are mainly parasites of concern in young horses. Small strongyles are resistant to benzimendazoles (such as fenbendazole-Safeguard) and to a lesser extent pyrantels (Strongid) in many areas of the world. Small strongyles are the main parasite of concern in horses over 18 mo. of age and also an issue in young horses. Resistance of small strongyles to ivermectin and moxidectin is not common, though it may be seen on specific farms where long-term use of a single drug (typically ivermectin) has been practiced. So, in a very young horse where you wanted to target ascarids, you wouldn't choose to use ivermectin or likely pyrantel (and certainly not moxidectin just from a safety standpoint). Likewise, in an adult horses (or a young horse) where you were targeting small strongyles you wouldn't want to use fenbendazole (Safeguard) as your first choice.

Moxidectin does kill 2 stages of encysted small strongyles (L4 & L5) which means that it reduces the risk of high numbers of small strongyles emerging from the intestinal walls after the adults are killed. It also means that there is a longer period from dosing to the reappearance of eggs in feces because it takes longer for adult parasites to be present in the GI tract. However, moxidectin also has a drawback in that the safety margin with this drug is much smaller than ivermectin and appropriate levels of body fat are necessary to ensure safe use. So, while ivermectin is not equivalent to moxidectin it can be used in younger horses, underweight horses and senior citizens who tend to have a lower body fat content with less risk of toxicity.

As for comparing ivermectin/praziquantel to straight moxidectin, I'm not sure what you are talking about. I didn't compare the products. The OP asked what drugs we use and what change in performance we have seen. I listed the drugs and the lack of change in performance. I certainly didn't compare the efficacy of the two products used. If I were to compare ivermectin/praziquantel to moxidectin without praziquantel, this would be my comparison:

Ivermectin/praziquantel: kills the same types of parasites as moxidectin though it is ineffective against encysted small strongyles where moxidectin kills two of the 3 stages of encysted small strongyles. The addition of praziquantel to ivermectin adds effectiveness against tapeworms which neither ivermectin or moxidectin kill. Ivermectin has a much larger margin of safety and can be administered to very young, debilitated and underweight horses which is not recommended with moxidectin.

Just FYI, I have a degree in veterinary technology which included classes in veterinary parasitology and pharmacology and have a special interest in equine parasite control. I've spent lots of time and money staying up-to-date on the subject and actually write continuing education for veterinary technicians on the topic. ;)

References:
Brady, H. A., & Nichols, W. T. (2009). Review: Drug Resistance in Equine Parasites: An Emerging Global Problem. Journal Of Equine Veterinary Science, 29(Proceedings of the 21st Equine Science Society Symposium), 285-295. doi:10.1016/j.jevs.2009.04.186

Samson-Himmelstjerna, G. v. (2012). Anthelmintic resistance in equine parasites - detection, potential clinical relevance and implications for control. Veterinary Parasitology, 185(1), 2-8. doi:10.1016/j.vetpar.2011.10.010

Reinemeyer CR (2012). Anthelmintic resistance in non-strongylid parasites of horses. Vet Parasitol. 2012 Apr 19;185(1):9-15. doi: 10.1016/j.vetpar.2011.10.009. Epub 2011 Oct 18.

Lyons ET1, Tolliver SC, Ionita M, & Collins SS (2008). Evaluation of parasiticidal activity of fenbendazole, ivermectin, oxibendazole, and pyrantel pamoate in horse foals with emphasis on ascarids (Parascaris equorum) in field studies on five farms in Central Kentucky in 2007. Parasitol Res. 2008 Jul;103(2):287-91. doi: 10.1007/s00436-008-0966-8. Epub 2008 May 10.

Matthews, JB (2014). Anthelmintic resistance in equine nematodes. Int J Parasitol Drugs Drug Resist. 2014 Oct 25;4(3):310-5. doi: 10.1016/j.ijpddr.2014.10.003. eCollection 2014.
 

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As for comparing ivermectin/praziquantel to straight moxidectin, I'm not sure what you are talking about. I didn't compare the products. The OP asked what drugs we use and what change in performance we have seen. I listed the drugs and the lack of change in performance. I certainly didn't compare the efficacy of the two products used. If I were to compare ivermectin/praziquantel to moxidectin without praziquantel, this would be my comparison:

Ivermectin/praziquantel: kills the same types of parasites as moxidectin though it is ineffective against encysted small strongyles where moxidectin kills two of the 3 stages of encysted small strongyles. The addition of praziquantel to ivermectin adds effectiveness against tapeworms which neither ivermectin or moxidectin kill. Ivermectin has a much larger margin of safety and can be administered to very young, debilitated and underweight horses which is not recommended with moxidectin.

Yes, I know these facts concerning safetly margins, age of horse and condition.
My comment was, it is hardly fair to compare one class of chemical dewormer against another, when the one de-wormer has an additional chemical added, against tape worms, and the other does not.
Would be more fair to compare both with the praziquantel added-Ie Quest plus versus Ivermectin Gold
 

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I didn't compare either in my initial post.

As for "fair" comparison of different drugs allows for appropriate choices in treatment options. That is why there are comparison charts out there for the different deworming drugs that list many different products with varying composition--to allow an educated choice to be made.
 

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Discussion Starter #8
Sue, Ryle, and Smilie
Thanks for your opinions, ideas, and references. My project is in its infancy and I value your insights very much. Though there may not be any obvious signs of health loss when a horse is infected and treated with the drugs that does not mean there are no long term side affects. Small strongyles do terrible things to the gut of the horse and can prevent the horse from nutrient uptake when they encyst. You probably can imagine that this means the horse will not be able to uptake vital nutrients fed to him or her and as a result have developmental problems. Over time this can amount to some great troubles and depreciation of the horse's value.

Though there is greater need for the development of more effective and dynamic drugs to combat parasite infection, my research focuses on the digestion itself. As I have previously said the effects on the health of the horse will not be very obvious. My original question sought to inquire whether owners noticed this and Ryle you gave me great advice to go to a vet! However, over time there might be problems associated with the drugs that are used. To give a relatable example, please do not take the severity literally, consider asbestos and how it was used to insulate homes for many years. It was thought harmless for a long time and then all of a sudden studies showed the danger of the compound to human respiration. Im investigating something along these lines; a common drug used for a purpose and the possibility and its ability to cause long term health related problems in the horse.

The bacteria that work with mammals in the gut, on the skin, and else wear outnumber the cells of that animal, humans also, 10 to one. These bacterial cells carry out a whole lot of functions. The ones I am worried about act on digestion. If a species of bacteria that is supposed to help break down food so that it can be taken up by the horse and use as energy or muscle building is depleted or maybe even lost due to a treatment than there we have a serious problem. Further investigation into this topic can really help you ladies and your horses out by providing pharmaceutical companies with a complete analysis of their drugs effects on gut biodiversity and encourage them to invest in research and development into more effective treatment plans.

I really appreciate any insight, suggestions or further articles that you have provided and anymore anyone can steer me towards.

Thank you,
Mike
 

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Sorry, Ryle, I mis read your original post, going back and reading it again!

'That being said:
Ivermectin use in 5 horses (ages 9, 11, 15, 19 and 35) produced no changes in performance
Moxidectin/praziquantel use in the same 5 horses has produced no changes in performance. '

You were answering the op's question as to effect de-wormers had on performance, with that data, and not comparing efficacy between the two.
Got IT!
 

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Hen running a small breeding stud farm I would rotate wormers each year. I wormed three times a year.

We took part in testing worms in sheep being immune to Ivermectin- which proved that they were.

Any horse new to the farm was wormed. We also had cattle and sheep grazing which can help with breaking down worm cycles.

We also poo picked.

The only times I have had adverse reactions is when a horse is heavily worm burdened and a 'strong' wormer has been used, this, one horse, having used Moxidectin, showed some strong colic symptoms. It did have a high infection of ascarids.
Another older horse in very poor condition, was just 'off colour' for 24 hours. After this I would use a five day dose of Panacure, give it a break and then worm with whatever I was using that year.
 

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As do I. No resistance is possible with DE since it kills mechanically instead of chemically. Does not affect the bacteria in the gut. win/win.
In controlled tests on goats and sheep feeding DE did nothing towards worm control.

I tried it and it was a failure.

The horses looked well enough but as the droppings were picked up daily and I rotated grazing with sheep and cattle, they have never been heavily worm burdened.

I fed it to the chickens for worming and that was a failure totally. As it was in killing Red Mite that can invest hen houses and will actually kill the birds.

Show me scientific papers on the effects of DE against worm control amd I might think differently.
 

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Mike, If I understand your post #8:

1. The horse in my avatar was 27 when I laid him to rest last Fall, he had been with me 24 years and always on a de-worming program to match our living environment and the time of year.

The De-wormers were rotational, as that thinking has only recently changed. He was such a drug-sensitive horse that half tablet of bute dropped him to the ground, yet he never had a negative reaction to worm meds.

We're they the underlying cause of his Equine Metabolic Syndrome, or his hind gut ulcers, or the strangulating lipomas that ultimately caused his demise via a major colic? I'm not smart enough to answer that but here's the info for speculation.

2. I rescued my now 29 yr old Arab 22 years ago. Once the vet cleared him, he began the same de-worming regimen as horse #1.

He has always been a hard keeper and has dealt with gastric stomach ulcers since 2005. He is not aging gracefully, something the vet says is common in certain Arabs, and has certainly become worse with the passing of his pasture mate of 22 years. Again, nothing I see that could be blamed on years of worm med.

3. I have another TWH who has been with me nearly 18 years, therefore the same rotational worming. He is now 21 and developed digestive issues 3-4 years back that were so serious the vet ran all kinds of tests and nothing. By digestive, I mean this horse could have set the barn on fire with his constant gas and I could hear him pass gas, 1,100 feet away, up on the ridge.

He finally cleared up with some prescription herbs and I am pretty sure his issues are tied to things he eats in the spring and fall.

Meaning, over the long haul, I have used every combo of de-wormers on these horses, including the dreaded Quest Plus. None of my horses ever had short-term reactions and I am hard-pressed to connect any of their current issues to long-term de-worming.

I hope this is in keeping with what you are looking for:)
 

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Very quickly -
I've been using wormers for many years
I've worked in two riding schools that both had a min of 30 horses/ponies where worming was done 4x a year
I worked for 10 years on a breeding/competition/selling/boarding yard where the horses including youngstock were all wormed regularly
I've had my own boarding/selling yard with a regular turnover of horses - all wormed regularly
Some of my horses/ponies were with us until they were in their late 20's and one in his 30's - all wormed regularly
I've used all the products you mention
I've never had any negative after effects from any of them

I often worked with local vets from mixed animal practices when they needed an assistant who was used to horses and I've seen many suffering terrible health problems from worm burdens due to lack of (effective) preventative medication and several that had to be euthanized when nothing more could be done for them as the damage the worms had caused was too great
And
I am getting sick of hearing about the use of DE as a wormer - it is totally useless when wet so it will not work - the moment it hits the saliva in a horses mouth its effectiveness is zero.
It is just some minerals and finely ground down silica and fossil shells - you might as well feed your horse fine sand - sand is silica.
 

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Mike, If I understand your post #8:

1. The horse in my avatar was 27 when I laid him to rest last Fall, he had been with me 24 years and always on a de-worming program to match our living environment and the time of year.

The De-wormers were rotational, as that thinking has only recently changed. He was such a drug-sensitive horse that half tablet of bute dropped him to the ground, yet he never had a negative reaction to worm meds.

We're they the underlying cause of his Equine Metabolic Syndrome, or his hind gut ulcers, or the strangulating lipomas that ultimately caused his demise via a major colic? I'm not smart enough to answer that but here's the info for speculation.

2. I rescued my now 29 yr old Arab 22 years ago. Once the vet cleared him, he began the same de-worming regimen as horse #1.

He has always been a hard keeper and has dealt with gastric stomach ulcers since 2005. He is not aging gracefully, something the vet says is common in certain Arabs, and has certainly become worse with the passing of his pasture mate of 22 years. Again, nothing I see that could be blamed on years of worm med.

3. I have another TWH who has been with me nearly 18 years, therefore the same rotational worming. He is now 21 and developed digestive issues 3-4 years back that were so serious the vet ran all kinds of tests and nothing. By digestive, I mean this horse could have set the barn on fire with his constant gas and I could hear him pass gas, 1,100 feet away, up on the ridge.

He finally cleared up with some prescription herbs and I am pretty sure his issues are tied to things he eats in the spring and fall.

Meaning, over the long haul, I have used every combo of de-wormers on these horses, including the dreaded Quest Plus. None of my horses ever had short-term reactions and I am hard-pressed to connect any of their current issues to long-term de-worming.

I hope this is in keeping with what you are looking for:)
Wow, this is very helpful. Unfortunately, I can not say whether or not the microbiota was the cause of your avatar horse's death. However, his case is very interesting and we probably could have learned a lot from him if he was around to study.

Your third case, however, strikes me the most. For my research I am focusing on the Gastrointestinal System. As food gets pushed through the intestines bacteria and other chemicals break down bigger pieces into smaller constituent pieces which eventually expose nutrients needed for a healthy horse. If your horse's gut had a bacteria, or lack of bacteria, for any period of time than there could be side effects resulting in terrible gas and other issues.

Your post was really insightful! Thank you so much. For me to tell you that worming regiments over a long period of time resulted these misfortunes would be inappropriate as of yet. However, I think you have experience that would be very helpful for me to get to the bottom of some of the issues I'm studying, at least guide me anyways.

If your up to it would you contact me [email protected] with the subject "HorseForumHelp"

Thank you very much!
Mike
 

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I have wormed with many substances over the years - including those in my youth where the horse had to be given a week off work to recover from being wormed.

Modern wormers are effective and despite all the fuss about resistance I have not yet found this to be true.

Over the years I have worked in stables with 100+ horses or more and myself owned many.

Now down to just 1 Clydesdale mare who I have owned since she was 6 months old - she is now 11½ - she has been wormed four times a year for all her life with Parade wormer - this contains Ivomec and Praziquontal. Her worm count is 0 and has been for several tests.

As she shares grazing with horses whose worming programs are not quite so regular I continue to worm her every 3 months.
 

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I am confused.

Anecdotal evidence - relying on people to tell you their stories of what they THINK wormers do to their horses - is not very scientific.

It would be much more valuable to actually measure before and after gut populations of a real horse or their poop.
 

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I am confused.

Anecdotal evidence - relying on people to tell you their stories of what they THINK wormers do to their horses - is not very scientific.

It would be much more valuable to actually measure before and after gut populations of a real horse or their poop.
You are certainly right. However my purpose for this thread is supplemental information gathering for the project. Hidden in peoples responses are insights and other information that, when i see it, prompts me to do further literature investigation. The benefits of that literature research helps me interpret the data and support my conclusions with stronger factual basis from both previously published work which i would have been led to by these responses and wet lab experiments.

here is my actual experiment
https://www.youtube.com/watch?v=yq6aeSmRToI

Thank you,

Michael Zulch
Elms College Biology
What's the Scoop on Poop
https://www.youtube.com/watch?v=yq6aeSmRToI
[email protected]
 
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