I think you missed my point. If lines within a breed known to bloat (or have HD[hip dysplasia]) have a higher instance of bloating, you can say, yes it is heredity. Those parents and that line produce a higher instance of the disease. Therefore, there is some trait, possibly physical that causes this risk. You would say the same for hip health. It is not really just big chested dogs. There is something people miss in saying this. If it was just because of broad chested dogs, then Deutche Dogges, GSDs, Irish Wolfhounds, and Dobermans and other narrow, deep chested breeds who are know to bloat would not. Again, in these breeds there are lines and certain dogs that can produce a higher instance, just like HD. We can create it through breeding (many test groups have been specifically bred to have HD or bloat for trials), but we can not totally pinpoint it or eradicate it. You have to remember that every breed starts with individual dogs. Breed tendencies are genetic by design. One of the first identifiers of an inherited disease or anomaly is if it is solely found in one or a few select breeds.