[noreins]

Another thread got me remembering that there are a lot of people that don't know much about HYPP (Hyperkalemic Periodic Paralysis) so I wanted to make a current thread for people to ask questions and get answers! I have studied up on HYPP a good bit over the past few years, I'm no expert but I can help answer questions as well. Both of my horses are NN thankfully but they are both by NH sires. And I have worked with NH horses and even an HH colt so I have some hands on experience too.

from UC DAVIS -"Hyperkalemic periodic paralysis (HYPP) is an inherited disease of the muscle which is caused by a genetic defect. In the muscle of affected horses, a point mutation exists in the sodium channel gene and is passed on to offspring."

To start, NH horses can still produce NH babies, even if bred to an NN horse. They have a 50% chance of passing on HYPP

- -N- H

N NN NH

N NN NH

An NN horse can not pass on HYPP even if they have an NH parent.

Breeding two NH horses gives you only a 25% chance on an NN foal, 50% chance of an NH foal and 25% chance of an HH foal.

- N --H

N NN NH

H NH HH

And an HH horse will always produce an HYPP positive foal even if bred to an NN horse.

- -H- H

N NH NH

N NH NH


- -H- H

N NH NH

H HH HH

AQHA will not allow HH horses to be registered, however no other registry regulates the registration of HYPP positive horses. NH horses can still be registered.

HYPP can be managed but not cured. HYPP+ horses need regular turn out and exercise. Their diet also needs to be carefully watched.

There are still people that will purposefully breed for NH horses because of the fact they tend to look more muscled and stocky and are much easier to fit. However, stress can be deadly to these horses.

An HYPP attack can kill a horse but does not always. However, too much potassium can very easily kill them.

I know I was a little vague so feel free to add more information or ask questions!

[HUS_WP_lovr]

I'd like add to add some common misconceptions some people have.

Both N/H and H/H horses can be symptomatic.

Attacks can happen anytime in a horses life. Just because the horse is 10 years old does not mean that he can ensured to be non-symptomatic. A horse that is non symptomatic today might be symptomatic tomorrow whether he's 2 or 20.

I'd also like to point out that there are HYPP N/N horses with just as much muscle mass or more. Halter breeders who believe their horse must be postive to win at Halter are wrong. Carribean Kid is a prime example of a heavily muscled stud that is N/N.




Also, Impressive(AQHA actually Appendix running bred) is the only stud that HYPP is known to trace back to. However one must consider the fact that DNA testing has not been required all of these years and an error could have been made.

APHA, AQHA, Appy, etc all can carry HYPP/have Impressive bloodlines along with any breeds with QH descendants/outcrossing allowances. Even grade horses. If your horse is exhibiting HYPP traits don't competely throw the possiblilty out.

[noreins]

Oh I love that stallion...

and I can't believe I forgot about the Impressive part ...

[KelosiasComb]

I have a question, are all HYPP H/H and N/H horses well muscled, or are there exceptions?

[noreins]

There are execptions but MOST of the ones I have worked with tended to be well muscled and if not then it didn't take much at all to get them that way. One mare only had to be on the hot walker for a little while everyday for like a week and she was already buff.

[KelosiasComb]

Thank you for the response!

I have a Quarab mare whose lineage is unknown to me, she's certainly not excessively muscled, and she doesn't bulk up any faster then any other horse when she's worked. So I shouldn't have to worry about getting her tested, correct?

[noreins]

That really isn't proof enough, I would get her tested, there is an animal genetics place that does it for 30 dollars.

[Yellowhorsesinc]

Do not let the looks of the horse fool you. A very heavily muscled horse can be N/N and a very smooth looking horse can be N/H. The only way to tell is to test.

[Earlywinefarm]

Originally Posted by Yellowhorsesinc

Do not let the looks of the horse fool you. A very heavily muscled horse can be N/N and a very smooth looking horse can be N/H. The only way to tell is to test.

Exactly!!!!!! I have an N/N mare that most woud think is N/H, but I had her tested. Lots of people would have bet lots of $$$ that she was N/H but I know from lots of experience that the only true way to tell is to test!!!

I have also seen quite a few that look n/n but were not. Looks are deceiving.

[KelosiasComb]

Good to know, in that case I'll certainly have her tested. Thanks much!