Hi there,
just a word of caution in case you have a TB or something, the DNA test is only useful for Type 1 PSSM and if your horse is a breed other then draft or stock horse breeding then you should still consider the biopsy.
Having said that, the test is def a huge breakthrough, and I am very excited it came from Stephanie Valbergs team (part funded by AQHA of course) here in my neighbor state of Minnesota!
I for one am HOPING that this means it will become something people test for alot sooner, and start helping these poor sore horses rather then "kicking and spurring their lazy backsides"!
best of luck I hope it all turns out ok.
Oh and as I can't remember if this link was given to you already here is the link for the Vets that developed the test and if you go to number 9 it gives you help to decide which test to go for.
http://www.cvm.umn.edu/umec/lab/PSSM.html