Hills prescription diet canine jd an innovative dog food which eases aching joints and preserves healthy cartilage to maintain your dogs quality of life results can be seen in 21 days can improve your dogs quality of life by helping them to play run and stay active more easily joint problems can occur when cartilage is worn away faster then it can be replaced cartilage acts as a cushion to protect the bones so when it wears away joints become swollen and painful causing mobility to be