Still confused about deworming


Maxine McArthur
 

I'm so sorry to take up the mods' time with non-urgent questions, but I am still experiencing some confusion about deworming protocols. 
Background: I have done Dr Kellon's Deworming course; I have researched evidence-based deworming and fecal egg counts; I have read the files here and have gone through the messages archives. 

I understand that less frequent drug treatment is now recommended in order to slow the development of drug resistance in small strongyles. However, I don't want to put my horses at risk from parasite-related problems by not deworming often enough, and I need to understand exactly what I am doing and why. I am particularly confused about the relationship between fecal egg counts and encysted small strongyles.

We have three adult horses on an eaten-down track with a dirt loafing area and 8 to 12-hour controlled grazing in small sections that are changed every 3-4 days. We remove manure from the loafing area and track daily. We have a small population of dung beetles that we would like to encourage. 

In Australia we do not have any moxidectin-only wormer--we can only buy Equest+Tape (moxidectin plus praziquantel), so if you want to target encysted small strongyles, you have to do a praziquantel dose as well. Plain ivermectin is available, also ivermection plus prazi.  We can get a combination of pyrantel embonate and oxfendazole that is said to be effective against small strongyles (but not encysted larvae) and tapes. 

The current advice seems to be: 
·         Use faecal egg counts (FEC) to identify horses which are higher shedders of small strongyle eggs.
·         Treating only horses with an FEC greater than 200 eggs per gram will mean treating less than half the population but provide around a 95% reduction in overall egg shedding.
·         Use one or two yearly treatments for all horses to control large strongyles, small strongyles, bots, tapeworms and other parasites.
·         Time the one or two yearly treatments for peak small strongyle larvae transmission seasons (usually spring and autumn). For one of these required treatments, consider using a treatment for encysted larvae (moxidectin) when small strongyle burden is at its peak (spring or autumn). 
 For reduction in shedding of eggs of small strongyles and to limit disease burden for susceptible individuals, higher shedders ONLY should receive one or two extra treatments each year.


My questions are about the relationship between the egg counts and worm infestations: 
1. Is it possible for a horse to have low shedding of small strongyle eggs in the manure, but still have a large encysted larvae burden? In other words, are we putting them at risk if we don't deworm more than twice a year? Dr Kellon's course material states: "
At any given time, approximately 90% of the Cyathostomes inside the horse are in larval stages, including encysted. Fecal egg counts are a very poor tool for determining Cyathostome infestation." and "deworming may therefore stimulate encysted forms to emerge. This also occurs in the late winter/early spring. When large numbers of Cyathostomes are encysted and emerge at the same time, extensive damage to the bowel can occur."

2. If a horse has been dewormed twice yearly with Equest plus Tape, is that enough to keep down the small strongyle infestation to a tolerable level? [given the paddock conditions above]--if yes, would the low shedding demonstrate this? if high shedding, would the answer be no, and mean that the deworming schedule needs to be more intensive for that horse? 

3. If I dewormed my horse last autumn with Equest and it is now spring, and her FEC is low--should I do a moxidectin + prazi deworming anyway, given that it is the peak season for transmission?

4. Is the point of FEC to identify high shedders and deworm them more intensively in order to keep the number of eggs in the paddock at a minimum? 

5. What are the recommended extra treatments for high shedders? 


Thank you so much for any advice. I have always been diligent in worming regularly and getting my head around less frequent, more targeted worming is proving to be difficult! 

--
Maxine and Indy

Canberra, Australia 2010

https://ecir.groups.io/g/CaseHistory/files/Maxine%20and%20Indy

https://ecir.groups.io/g/CaseHistory/album?id=933

 


LJ Friedman
 

Because my horse is
old 28 and has Cushing’s and IR and probably a not so good immune system,I use ivermectin monthly and twice yearly I worm for tapes. But I will not use prazi quantal as that pose a problem for triggering some laminitis.



--
LJ Friedman  Nov 2014  San Diego, CA

 

 

https://ecir.groups.io/g/CaseHistory/album?id=2117 ( https://ecir.groups.io/g/CaseHistory/album?id=2117

. https://ecir.groups. io/g/CaseHistory/files/LJ% 20and%20Jesse ( https://ecir.groups.io/g/CaseHistory/files/LJ%20and%20Jesse )


ferne fedeli
 

My vet recently told me to do fecal tests and not to continue worming regularly unless it is indicated by the tests.  I just did the tests and all my guys were negative.  I imagine she will want me to do some worming at some point, so need to get back to her and ask what to do in the future.

--

 Ferne Fedeli

No. California

Regional Members Database Coordinator

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--

Ferne Fedeli

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Debra Trujillo
 

My vet thinks this is what happened to my horse, Abby.  

"1. Is it possible for a horse to have low shedding of small strongyle eggs in the manure, but still have a large encysted larvae burden? In other words, are we putting them at risk if we don't deworm more than twice a year? Dr Kellon's course material states: "At any given time, approximately 90% of the Cyathostomes inside the horse are in larval stages, including encysted. Fecal egg counts are a very poor tool for determining Cyathostome infestation." and "A deworming may therefore stimulate encysted forms to emerge. This also occurs in the late winter/early spring. When large numbers of Cyathostomes are encysted and emerge at the same time, extensive damage to the bowel can occur.""

I had done fecal egg counts on my horses in early spring.  Both came back with zero egg counts, so I wormed in the spring and then did not worm again until fall (6 mo.).  It was October.  I wormed with Ivermectin at evening feeding.  The next day, after feeding the horses, Abby's heart rate went sky high, became sweaty, started to poop a lot to the point of if being loose like cow pies.  The vet said to take her to the clinic pronto.  A long story short, Abby was diagnosed with Colitis, was in intensive care for 7 days, got through it and has not had another bout since, thank the Lord.  The vets do not know for sure what caused it, but think, since the only thing different was being wormed, that the ivermectin must have killed off stongyles in the gut that then triggered the encysted strongyles to come out, causing a highly toxic condition in the colon.  Now, since that happened, I worm every 12 weeks, switching between ivermectin, moxidectrin, and strongid (fenbendazole is said to not work anymore, unless you do the 5 day worming).  I give Abby banamine the night before, the day of worming, and the next day just in case there is anything that would cause inflammation.  If she starts to have runny stools after worming, I also give her psyllium for a couple of days, plus  1 Capsule of Saccharomyces Boulardii+MOS once a day for about 3-4 days.  Both my horses still have never had any egg counts in fecal tests, but I will never worm only twice a year now.      
--
Debbie and Precious
June 2017, Parker CO
Case History:  https://ecir.groups.io/g/CaseHistory/files/Debbie%20and%20Precious  .
Precious' Photo Album:  https://ecir.groups.io/g/CaseHistory/album?id=6846  .



Eleanor Kellon, VMD
 

On Sun, Nov 12, 2017 at 05:17 pm, Maxine McArthur wrote:
My questions are about the relationship between the egg counts and worm infestations: 
1. Is it possible for a horse to have low shedding of small strongyle eggs in the manure, but still have a large encysted larvae burden?
Yes, it's definitely possible. For example, egg-laying decreases at certain times of the year.

In other words, are we putting them at risk if we don't deworm more than twice a year?
It depends on the horse.

2. If a horse has been dewormed twice yearly with Equest plus Tape, is that enough to keep down the small strongyle infestation to a tolerable level? [given the paddock conditions above]--if yes, would the low shedding demonstrate this? if high shedding, would the answer be no, and mean that the deworming schedule needs to be more intensive for that horse? 
The horse is protected by a combination of his own innate immunity and low exposure. Strategic deworming as you approach peak pasture season reduces exposure while deworming at the end will remove any accumulated parasites and yes, low shedding would confirm at least during peak egg laying season. The problem is that studies are now consistently showing egg counts are reappearing as quickly as 30 days after deworming, even with moxidectin. This may be because small strongyle strains with a short life cycle are being selected or because late stage larvae are not as susceptible to removal as they used to be - or both. In any case, a horse with a significant egg count after 30 days is a high shedder and needs to be dewormed monthly to protect both himself and the horses around him.

3. If I dewormed my horse last autumn with Equest and it is now spring, and her FEC is low--should I do a moxidectin + prazi deworming anyway, given that it is the peak season for transmission?
It's optional but I would do another FEC in a month or so to make sure she doesn't need it.


4. Is the point of FEC to identify high shedders and deworm them more intensively in order to keep the number of eggs in the paddock at a minimum? 
Yes, and also to protect that horse.


5. What are the recommended extra treatments for high shedders? 
As above, it may be as often as every 30 days. You can use ivermectin when deworming this often.





 
--
Eleanor in PA

 

www.drkellon.com 

EC Owner 2001


Maxine McArthur
 

Thank you, Dr Kellon! This clarifies things. 
And thank you for the other feedback--Debbie, that is exactly the situation I am afraid of, thanks for sharing your experience. I'm glad Abby hasn't had a recurrence.
--
Maxine and Indy

Canberra, Australia 2010

https://ecir.groups.io/g/CaseHistory/files/Maxine%20and%20Indy

https://ecir.groups.io/g/CaseHistory/album?id=933

 


 

Our two horses have not been wormed this year. One is IR, the other is not.  They are the only two horses on mostly dry lot pastures seven months out of the year with the non-IR horse on pasture two hours during the day for the remainder of the year  (rainy season +2 months).  We have done FEC three times this year. The results were no parasites.  I am worried that we could be creating a situation such as the one  that Debbie shared. Is our vet in error telling us not to de-worm?
--
Robyn & Toons
North Bay, CA

April 2016

https://ecir.groups.io/g/CaseHistory/files/Robyn%20and%20Toons

https://ecir.groups.io/g/CaseHistory/album?id=9117

 


 

I'm confused about the peak and low seasons.....I'm located in south Florida, which is warm and wet for the majority of the year, so I am not certain if we have a peak and low season? 

We currently have six horses on site, and all have access to shared pastures daily.  We perform FEC every 4 weeks, any horse with FEC over 250 is treated with Ivermectin, and we use Quest Plus in March and November, regardless of FEC.  I also treat any new intakes with unknown deworming history with Ivermectin once every three weeks for two doses, then Quest Plus on week 9.
--   
Cami Kanner

 

Vero Beach, FL

0815   HhH H ow


Maxine McArthur
 

Cami and Robyn
I'm interested in your manure management strategy, as it seems to me that will influence the amount of worm larvae that a horse has access to ingest. Do you pick up manure or leave it, do you rotate grazing areas, do you have dung beetles? 

Moderators, if this topic is better suited to Horsekeeping I'll move it there. 
--
Maxine and Indy

Canberra, Australia 2010

https://ecir.groups.io/g/CaseHistory/files/Maxine%20and%20Indy

https://ecir.groups.io/g/CaseHistory/album?id=933

 


 

I am interested in this topic because I have often wondered how my horses could possibly have worms when we pick up all manure on their dry lot daily. 

Gail Russell July 2008 Forestville CA



Sent from my Verizon, Samsung Galaxy smartphone

--
Gail Russell 8/30/2008

 

 https://ecir.groups.io/g/CaseHistory/files/Gail%20and%20Brother%20-%20Odin%20-%20Decaffe%20%20-Gunthar .


 

Hi Maxine, 
We pick up manure all day. The property owners do morning and evening pick up and my pasture mate and/or I do pick up while we are on the property. One or both of us is on  the property every day. There is grass and weeds in some of the pasture paddocks and sand and dirt in the paddocks where my IR horse lives in (although I am starting to see little green seedlings popping up). Anyway, the property is mucked all the time and the muck is put in a covered bin after pick up.
--
Robyn & Toons
North Bay, CA

April 2016

https://ecir.groups.io/g/CaseHistory/files/Robyn%20and%20Toons

https://ecir.groups.io/g/CaseHistory/album?id=9117