I always knew a hip cap as the top part of the cow's hip has been knocked off and she now appears lop sided. Dairy cattle is all I have ever seen with a capped hip. Happens during calving or when they fall just right. We had one do it cutting the corner under the gutter cleaner. Caught her hip and the next time I looked she was crooked! Never appears to hinder movement or production just doesn't look "show ring ready" anymore.