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  Discussion on HYPP or ?
Author Message
Member:
leec

Posted on Tuesday, Mar 22, 2011 - 5:44 pm:

Hi DrO,
Are there any other diseases/conditions other than HYPP, where muscle tremors can be the only outward symptom? Our 7yr old Quarter Horse mare had an episode yesterday that strongly resembled an HYPP attack from what I've read, videos I've watched, and in talking to my vet. I've never witnessed this with her in the 2 yrs we've had her. I was tacking her up when the tremors began - from her throatlatch down her neck across her chest, shoulder, and along her sides to her flanks. She was not distressed and was just standing dozing. I led her around and the tremors disappeared after about 15 mins. She is an unreg'd horse, but she is well muscled and looks 'halter bred'. I am having her tested, but in the meantime I wondered if there is something else I should be considering.
Thank you,
Lee C
Member:
rein

Posted on Tuesday, Mar 22, 2011 - 8:27 pm:

What about tying up? A girlfriend had a mare that the vet said that was what was wrong. Yes even though it would sometimes happen before a workout too???
Moderator:
DrO

Posted on Wednesday, Mar 23, 2011 - 8:08 am:

Lee any disease that causes weakness can cause trembling so not only diseases of the muscle but diseases of any major organ symptom, spinal cord and peripheral nerve disease, endocrine disorders, are possible. Cold temperatures and nervousness also can cause trembling. Lastly seizures are a possibility.

The first step is not a set of possible rule outs but an attempt to find the general system effected causing the trembling and from their a list of possible diseases can be considered. Besides a good physical exam a complete set of chemistries and CBD will rule in and out many diseases. For instance a sample taking during trembling that has normal electrolytes, in particular potassium, is unlikely to be due to HYPP and several other possibilities.
DrO
Member:
paul303

Posted on Thursday, Mar 24, 2011 - 12:19 am:

Just an experience I have with my 18 yr old App. mare: Had her since she was 13. Each year between the months of April and August, she's had a severe muscle spasm along her side...one side, or the other or, rarely, both. She gets very agitated during these "spasms", biting frantically at her sides and going after the other horses. She also sweats profusely and rolls rather violently. I thought it was colic at first and treated with banamine - it always responds in about 40 minutes. But when I noticed a pattern where it seemed to occur at 30 day intervals, I called the vet. Although she's never witnessed the actual "spasm"(where the muscles- I guess they're the abdominal oblique and trapezius- twitch, bulk up and become hard)she ran blood (normal), did a rectal and did a sonogram. She did this twice and the only thing she found, both times, was a rather large follicle. The older the mare gets, the less the spasms occur....however, they still seem to correspond to the same time of the month and only in spring and summer. Two years ago, there were only two, and last year only one. We've chalked it up to "her time of the month" while passing a large follicle.

Not saying that's what you've got, just throwing it out there.
Member:
leec

Posted on Friday, Mar 25, 2011 - 1:21 pm:

Thank you all for your input.
Michelle, I’ve seen horses tye up and this was nothing like that – she was not in distress and not at all reluctant to move or sore when I palpated her.
Lee, I suppose this could be the very beginning stages of what you describe. However, this is a mare that other than a bit more peeing you can’t tell if she’s in heat. Even if she’s around new horses, her behavior/attitude never changes.
DrO, it is interesting that your advice as to where to start is the opposite of what my vet has recommended... She has suggested the HYPP test first; as it is the cheapest place to start (costs less than her call fee). I will think some more on this.
I’ve gone back and racked my brain from since I purchased the mare and made note of some things that might shed some light when they’re all put together...
We purchased the horse and she was delivered by a hauler in April 2009. It was a 4 hour haul, and the hauler commented that she unloaded and watered @ 2 hours and had never seen a horse drink so much. When the horse arrived she was not sweaty and did not appear stressed. She was delivered to a friend’s place initially. She was there for a week and my friend also commented that she drank a lot (no other symptoms). The horse came home and her water intake was by then more appropriate – wrote it off to stress/dehydration from the trip. Her b/s was about a 6 when we got her.
We immediately noticed she was very easy keeper – our joke is she could maintain condition eating rocks... However, she was not used much that season, so not getting any forced exercise either. I did notice right from when we brought her home that when she had her head down eating hay her breathing was noisy (this is even louder when she is heavier). I previously had a horse that did the same and a vet had said that some just do (breath noisier).
In April of 2010 she went to a trainer for a tune-up. She had gained weight over the winter and her b/s was about an 8. The trainer noted she was somewhat exercise intolerant. When her heart rate increased she seemed to have problems breathing – at one point threw her head up and staggered backwards. So the trainer initially worked her in 2-3 shorter segments throughout the day and put her on a diet. After a couple of weeks she was fine and we continued to work on keeping her b/s at a 5 or 6 throughout the summer and had no other problems with her. However, when she would get stressed under saddle and if her poll was flexed (face vertical), her breathing was louder. It is rare that she gets 'worked up'. She is a very quiet horse – lazy and not spooky. One thing that surprised me at the trainers is she cribbed. She was however confined to a dry-lot and on a diet, so I felt this was due to boredom. At home, we have several acres and other than occasionally 'tasting' a rail or tree, she does not crib. As for diet in the 2 yrs we’ve owned her, we feed a grass mix hay year round (about 80% grass/20% legume). We live in the ‘rocks’, so not much pasture in the summer. The horses always have water and it’s heated in the winter. She originally had a salt/mineral block and did not touch it. For fear of her not getting enough salt, I changed that to just a plain salt block, which she spends more time at than her pasture mate. I have never given her concentrates. It’s now spring again and her b/s is again up to an 8. As we are starting to think about riding, I was going to put her on a diet. I’m wondering if I should hold off on that, as if this is a case of HYPP, from what I’ve read fasting is not a good idea. I can feed her several times a day, but it would be super hard to take weight off her without decreasing her feed significantly.
Lee C
Moderator:
DrO

Posted on Friday, Mar 25, 2011 - 6:43 pm:

Maybe she will hit a homerun with the HYPP or possibly she sees something more definitive? Is there a confirmed link back to Impressive?
DrO
Member:
leec

Posted on Saturday, Mar 26, 2011 - 11:15 am:

We don't know who my mare's dam is, but there is Impressive on the bottom side of her sires pedigree. When we bought her I found out who the breeder was and contacted them and asked them if they could tell me anything about the dam (just my curiosity). They confirmed by email that our mare was 'one of theirs', but gave us no info on the dam.
I've couriered a hair sample from our mare to UC Davis and we should have the HYPP test results within 2 weeks. AQHA won't do an HYPP test on a horse unless both parents are registered with them.
Lee C
Member:
leec

Posted on Saturday, Mar 26, 2011 - 1:18 pm:

I just found out from AQHA that the sire is HYPP/NN.
Moderator:
DrO

Posted on Saturday, Mar 26, 2011 - 4:34 pm:

I am confused by your post Lee. The normal gene is designated by a "N" and the abnormal gene designated by a "H". So a horse with no HYPP mutated genes (has two normal genes) is said to be "NN". A horse that is heterozygous for the HYPP mutation is designated "HN". You seem to be suggesting there is one HYPP gene and then two normal genes: a triploidy???? This is gone into detail in the article, so review it and see if you can straighten it out.
DrO
Member:
leec

Posted on Sunday, Mar 27, 2011 - 12:01 pm:

Sorry to confuse. I just found out that the sire is HYPP/NN (didn't have this info when I started the discussion). However, we don't know who the dam is and if she has Impressive breeding. I think I have it right - now that we've eliminated the sire, my mare can't be positive unless her dam was HN or HH, correct?
Moderator:
DrO

Posted on Tuesday, Mar 29, 2011 - 7:35 am:

If the sire has no HYPP gene and the mare has no HYPP gene then the offspring cannot have HYPP.
DrO
Member:
leec

Posted on Thursday, Mar 31, 2011 - 10:51 pm:

Well, not good news today. The results of her HYPP test are NH. I've read all about the management of the disease and different people's experiences with it. It is difficult to tell how severe her case is, but this mare is my husbands who is a beginner rider, so I don't want him riding her anymore. Unfortunately, we are not in a financial position to keep a horse that can't be used. I have contacted some horse rescue places that will take her and re-home her as a companion horse only. Although my gut suspected this was going to be the case with her, I am a little in shock and very sad - this is a sweet mare...
Lee C
Moderator:
DrO

Posted on Friday, Apr 1, 2011 - 6:44 am:

Sorry to hear this has turned out poorly for you Lee.
DrO
Member:
lilo

Posted on Friday, Apr 1, 2011 - 9:43 am:

So sorry to hear about this outcome, Lee. Hoping that you find a good home for her as companion horse.
Lilo
Member:
theresab

Posted on Friday, Apr 1, 2011 - 12:57 pm:

Sorry to hear the poor outcome, Lee. Best wishes for finding her a good new home.

Theresa
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