True weak pasterns will shown up in heavy bred heifers. Or at least the most severe cases. Calve them, cull them, chunk out the semen. Older cows can seemingly founder, if the bloodline has that tendency, on great periods of lush grazing and the rear feet struggle to correct themselves more than the front hooves. Those are bloodlines to watch. For any cattle, a balance in perceived body length, leg length, a check of stride, a check of pasterns and hoof claws and avoiding the swayback bulls will fix 95% if those which do not make the cut get out of the genepool. Goldilocks was right: they can be too long, too short, too tall but I want them "just right".
The best thing about videos of sale cattle are the views of foot placement while walking. It tells so much. As a cow ages, if she injures one hoof or leg and a hoof or claw heals improperly, I do not see that as a culling offence if she can keep doing her job. All opinions.