I would like to hear from Pam also. However, my understanding (waiting for correction) is that the condition does not require the weight of a rider to manifest, although it becomes blatantly more visible. It does require someone knowing how a horse should move, as opposed to how it does move. Also, males of the El Bataa line do not exhibit, nor do they pass the trait along. It is only the tail-female females of that line. Shiko Ibn Sheikh being an example of a male of that tail-female line that did not exhibit or pass on the trait. This is my understanding, at present.
Ray, It is ABSOLUTELY NOT TRUE that the BeB males don't have or pass on the "Hop". I do agree that Shiko Ibn Sheikh apparently DID NOT have the problem, nor did he seem to pass it on.
My "Babi" had it & did pass it on, but only a couple of times. The BeB son Night Visitor was very compromised & lost young to the condition.
Ray, & everybody else who is intersted take a look at Lisa's (Flying Hooves) Yahoo Group for a partial listing of affected BeB's. Kindly compiled by SZEDLISA. I have the list but to 'puter stoopid to post it here. I'll email it to anyone who is interest.
Going to take a big drink of something strong & take myself over to theedarkside & see if the old BeB thread survived intact.