In this condition, fragments of bone or cartilage become detached within joints. An affected dog limps inconsistently as a fragment moves around, sometimes limping, sometimes moving normally. In Bull Terriers it is usually the stifle or hock which are affected. The fragments may be removed surgically. Bull Terriers are said to be predisposed to this condition, but there is no evident mode of inheritance, indeed it may have dietary causes. It is suggested that osteochondrosis may be caused by an excess of calcium in the diet of the developing puppy. Unfortunately there is a tradition of feeding substantial quantities of calcium supplements to Bull Terrier puppies because the dogs are so heavily boned, hence the reported predisposition. In fact no supplementary calcium should be fed to Bull Terriers (in pregnant bitches it predisposes to eclampsia (milk fever) after whelping). It should be noted that most manufactured dog foods, both dry "complete" and canned, contain more available calcium than is desirable for this breed.