Not only is a shortened ERP an issue and has been around for several years, even if the kill rate is still highly effective, but some actual resistance to actually dying is there on some farms
A farm in KY imported some TBs from Ireland who carried strongyles that were HIGHLY resistant to moxidectin. Likeā¦WTH did those guys to do speed up the resistance that badly!!! Thankfully the farm has always been on top of a very hands-on deworming strategy and caught it right away, and with some assistance were able to kill the strongyles. But good God, how many of those TERRIBLY managed horses are in the US in the hands of people who donāt know squat about proper deworming!!!
They absolutely are not terribly managed horses at all. It is very likely a case of they werenāt as meticulous as the US operation in their testing and didnāt see it. This is very likely the case on many farms. Resistance is inevitable, regardless of good management. At this point we are just trying to slow it down and desperately trying to get people to listen and fund projects to try and find alternatives.
Martin also published a paper recently discussing one of the parasitology herds that hasnāt been dewormed in a few decades. It basically boils down to them being perfectly healthy. Good weight, healthy coats, healthy foals. We deworm to control burden, not to get rid of all of the parasites.
Also, @JB, Iāve shown him some of the threads on here and he asked if you were either me or another of his students because you give good answers to parasitology questions. Iām sure heād love to have you if you ever wanted a PhD!
Yes, youāre probably right, and my comment was an overreaction I just canāt imagine what the practices were that led to such high resistance to moxidectin
Iāve read that! Itās pretty awesome for sure, and speaks to the ENTIRETY of managing a horse, from hoof care to diet to all of it.
Iām so honored! He is definitely a mentor from afar, and I point people to his research All. The. Time.
Funny thing - my initials are also JM LOL Just a different letter in the middle.
For example, anything coming out of any sort of high traffic boarding facility with group turnout almost always has a higher FEC with a poor FECRT, regardless of their parasite management.
Itās usually not that they are employing poor use of dewormers, its the number of horses sharing communal space. And thatās a problem thatās hard to correct. You canāt just say ābuy more land so you can rotate turnouts more often.ā
Heās kinda āthe manā when it comes to equine parasitology. Also an overall awesome person and fun to work with. If youāre ever in KY hit me up and Iāll take you to visit the lab.
Outreach and convincing horse owners/vets/farm managers to do FECs, FECRTs, and deworm less is a huge mission for those (very few) of us who research equine parasitology. So, I will pose the question to the group: How can we help? Dr. Martin Nielsen (one of the top equine parasitologistsin the world; he wonāt let me say heās number one (but he kinda is)) has a YouTube channel with informational videos, a Twitter account, publishes articles in many magazines, and also played a huge role in the AAEP guidelines. What else would be helpful for you? Or how could we better reach people?
This (hopefully) probably has more to do with a compromised immune system due to the overall housing/general management/stress of the environment. Do you have any of those horses long enough to see if they start to manage things on their own?
I have heard that about him! he comes across that way in his videos as well. I would be so geeked to visit!
sigh itās frustrating. The answers, whether from big barns or āsmallā people with 1-2 horses, are that they simply donāt care because āIāve always done it this way, my FECs are clean so clearly itās workingā, or āitās easier to just deworm everyone 4 times a yeaā or āthey live out in herds, I canāt do FECsā, or "we have too many horses coming and going, itās just easier to do everything the same way ", and more.
I personally have these discussions on a very regular basis in a couple of FB groups. I show them the AAEP article and pull out some of the most pointed comments about resistance. The sad thing is, many of the people I show that to say āmy vet knows what heās doing, Iām going to listen to himā and proceed to ignore the entirety of the AAEP
When vets arenāt on board, when they are perpetuating the old methods, itās really, really hard to get people to start to understand the āknow better, do betterā
āThoseā people wonāt watch videos. They barely read even short articles and when they do, the often pull out one comment that on its own seems to support their opinion
I honestly donāt know, other than it HAS to start coming from the ātopā down, ie the vets.
PS - Iād love to connect with you in real (online) life if you are up to it. If so, shoot me a message. If you prefer not to, I totally understand!
Iām just one little person in one little remote corner of the U.S., but after reading several similar threads in the recent past in which youāre a major contributor, and now following this one, Iāve done a lot of extracurricular research and reading to educate myself (as best I can) and have updated my deworming plan to follow current recommendations. So JB youāre not talking to a wall! I have four horses, closed herd, living at home. Iāve been deworming āthe old wayā for nearly ten years because until recently I didnāt know any better. When my first two horses arrived I showed my vet the previous ownerās deworming schedule (old way) and was told āLooks great!ā. Ten years on, now that I know a bit more, I was at first a little aggravated at that memory. After watching one of the videos you recommended on thehorse.com, where the speaker defended vets (to a point), I understand and appreciate that my vet runs a small, rural vet practice (horses + everything else) and they likely donāt have the time or patience to try to educate some of the local folks who, as stated on this and other threads, have "always done it this way.ā So rest assured your message is resonating with at least one very interested reader!
Itās a good point about compromised immune systems, however many of these farms are high end with top notch management, not just āboarding barnsā with typical corner cutting like too little forage.
My working theory is itās the horse turnover compounding the problem.
From my own anecdotal experience, in a closed herd with good management, it takes about a year and a half to two years for significant shedders to begin managing their parasite load to the point where you consistently have little to nothing show up on FECs. But if you are constantly introductory new horses to the mix, you are continually introducing new populations of parasites for even the healthiest of horses to manage.
If you rest the field as frequently as recommended, you can cut down on transmission and break the life cycle. But how many farms can truly afford to do that?
I have! When I first brought my old man (18 at the time) home from a 60+ horse boarding facility, he had a very high FEC. I donāt have his results accessible right now but within a year or two he was down to negative and has been negative or very low every time since then (8 years), even with other horses coming and going (not as often as at a large boarding facility, obviously).
I will echo this too. When I moved my horses home I have to admit I was not very up on deworming protocols as they had always been handled by the boarding barns. My vet suggested old-school rotational deworming. It was due to reading threads on here that I questioned that, and @JB and @Texarkana were instrumental in helping me understand the current best practices. I think there is an old thread of mine on here somewhere about it! Now that I understand it, itās not so confusing, but there are definitely better and worse ways to explain it and you two are good and generous with your explanations. Thank you!
Iām not sure I get what you mean. Bringing in more eggs? Different species eggs?
I DO think that if even healthy horses are overwhelmed by large populations of strongyles on a regular basis, their system can be overwhelmed. There are ways to mitigate that by deworming the newbies once they get to the new place. NOT the old way of ādeworm before they get thereā, but the more current way of deworming once there, so that the small % of inevitably resistant strongyles are in the pasture highly diluted by the non-resistant ones. Otherwise, that pre-dewormed horse is dumping only resistant eggs into the pasture. If you want more reading on that, using ārefugiaā and ādilutionā in search terms will bring up some good stuff
Love it!
YAY! I KNOW it can be a lot to take in at first. Thatās where most people seem to just tune out and go back to the comfort of what theyāve always done They arenāt terribly interested in learning unless they think itās going to be quick and easy. If not, they check out.
Not new species, I mean horses say farm A has more resistant small strongyles than farm B due to poor practicesā¦ when a horse from farm A moves into a herd at farm B, now everyone in that field is contending with a different level of resistance than they were before. You have changed the dilution of the refugia. When that is happening regularly and horses are coming in and out of herds, my observation is that is seems to cause FECs to creep up in spite of good deworming practices.
My own holes in knowledge and misconceptions are probably preventing me from articulating this clearly.
The flaw with deworming when you get there is that some horses move a lot. If good record keeping doesnāt happen, then we are just pushing dewormer into these horses as much as rotational days. Iām not disagreeing with you when I say that, Iām just acknowledging the reality.
Iām not too confused as to what I should generally ādoā to my horses. Itās the when that is confusing to me. Fall and Spring by the calendar tend to be āstill summerā and āalready summerā here in FL. My vet is comfortable with twice yearly deworming with Equimaxx or Quest Plus. But so far doesnāt seem to have an opinion on actual timing. And as weāve seen here, the UF guidelines are a bit suspect.
Do I do better to time āSpringā dewormer so that the end of efficiency occurs as temps heat up enough to provide environmental kill? Or does that leave my horses more vulnerable to summer sores?
Fall deworming after āhard frostā is going to translate to mid winter here (if at all). So thatās not terribly helpful for me.
I donāt want to contribute to resistant worms, kill dung beetles or risk my horsesā health.
Itās true, there is unlikely to be any deworming history following a horse around. If people would only do the right thing, that wouldnāt matter
But, there IS still value in deworming once heās there, not before heās put into the pasture.
If the only thing he ever deposits is resistant eggs (eggs from resistant adults, you know what I mean ) over the next weeks, then heās increasing % of resistant infective larva the other horses are consuming
But if heās depositing both resistant and non, and the other horses are also depositing a small % of resistant but also some small number of non-resistant, then the resistant population is diluted
the more diluted the resistant population, the higher the % of non-resistant strongyles each horse has, to be killed at the next deworming
This still falls into the same strategy - if you donāt get hard freezes, of they are maybe once in January, then roughly every 6 months, Spring and Fall, is what you do.
Donāt deworm when temps are reliably above 85* unless absolutely necessary
This means most of even the South can deworm in March/April, and Oct-ish
Summer Sores are a whole 'nother ballgame, not related to strongyles, so you do what you have to do. You shouldnāt use ivermectin to prevent SS, but do use it as necessary if you have an infection
Do the Fall deworming around 6 months after the Spring deworming.
You can check with your extension agency. I donāt know how dung beetles are in the deeper South, in the Fall, Here in the mid-Atlantic/SE area, they arenāt very active past early Summer or so. Itās not just about heat, as FL is hotter, earlier, more regularly, than NC is. Even in NC they just arenāt active (much) in the Fall when temperatures are similar to that of Spring.
Well the wormer manufacturers have not read the current literature that is for sure. I did one of those Facebook quizzes where you answer a few questions and the company plans out your worming schedule. The survey NEVER asked about fecals - are you doing them on a regular basis? What have the results been? I donāt remember the company - Zoetis, Merck, etc. but they advised me that my mare who has zero counts on her fecals be wormed SIX times a year because she is on a small pasture. I donāt remember all the products they recommended but about half of them are not effective anymore. They just wanted to sell me a bunch of their products.
Iām sure they have. But to re-label things requires new FDA-approval, which is $$. This means itās still āokā for them to suggest what they were labled for, which was way back when the strategy WAS 4-6 times a year. Itās not in their best (legal?) interest to suggest anything off label.
Yeah this is definitely an issue. Most vets only get a small amount of parasitology in school and then never update their knowledge or just forget a lot of it. It tends to be the ādark horseā discipline, or at least thatās the running joke amongst veterinary parasitologists.
Itās important to remember that vets know a little bit about a lot of topics, and there are people who know a lot about very specific topics. Even if the letters after our names arenāt (always) DVM, we still possess valuable knowledge!
I just canāt imagine what the practices were that led to such high resistance to moxidectin 
