Just saw one of the programs the other day: it was mentioned that his grandmother had the same problem, suggesting there may be a genetic element.
I do wonder if sometimes it might be better to allow a subspecies to go, or to be 'diluted' with outside genes, rather than breed from animals with genetic problems. In this case Tejas's problem has not been a long-term welfare issue, and I guess if it is genetic then it will be possible to breed the problem out in future, so I'm not totally against breeding him. But the question is still maybe valid. (I'm especially thinking of Cheetahs, where personally I'd advocate breeding Asian to African subspecies, as the species is so lacking in genetic diversity anyway. The same might be true of many zoo species, even if it's not true in the wild. If we are looking to have stock to re-introduce in some future where human population has reduced enough to allow it, then maybe it's more important to have healthy lions/cheetahs/whatever than subspecies that came from an area in the first place).
Trust me to be controversial on my first post here *G*