Originally Posted by Brookside Stables
Our yearling has Impressive 5 generations back. I have not tested her yet but plan too only for possible future breedings.
If there is a question as to the possibility of your yearling carrying the HYPP genes then you should want to have her tested in order to properly care for her should she be HYPP/NH or HH. There is a special feed regimin that you'll want to follow and then some basic supplies you'd want to keep handy such as glucosomine should she ever have an attack. It will also change the way you handle her when showing and transporting.
Actually, now that I think of it...Beginning with the 2007 foals, all Impressive progeny are required to be parentage verified and HYPP tested subject to the conditions listed in rule 205. Any that test H/H will not be eligible for registration.
You may not have to test her though since you have papers. Just check the last known Impressive relative, what I'm saying is follow the trail to the final Impressive bred horse. If the trail ends at one horse and that horse is HYPP/NN then the gene would not have been passed and your horse will be NN.
I am surprised at some of the ignorance in these responses and by ignorance, I mean that I can tell that some of the folks posting don't know much about the desease, they know enough to understand it but not really the mechanics. An article would be good I think.
As for the comment you made about it being strange that they misdiagnosed so much, you want to look at it as, a new disease. They had no knowledge of it's existence because it hadn't been discovered yet so you have to rule out all the things that it's not before you realize, wait, this is something new. Then they have to figure out what it is and why it's happening, and of course they have to figure out where it came from. This is where a lot of people act like Impressive was a bad horse and the people that bred to him were "idiots" and they don't realize that no one knew it existed or where it came from.
I have 2 Impressive breds, they are line bred top and bottom. A mare and a gelding. Both are NN. I love the line, I'd buy another in a heart beat. (NN).