Most veterinarians are in a habit of recommending you get your dog spayed or neutered at 6 months. Though this is a standard protocol, it is not one that I recommend for your rapidly growing, large breed, sporting dogs. Abnormal growth that results from having some growth plates close on time (due to the presence of sex hormones) and having some growth plate closures delayed (due to the removal of the testicles or ovaries) can in turn, dramatically increase your risk of orthopedic issues. The growth plates of the long bones will close generally between the ages of 5 and 14 months. If you have your dog neutered at 6 or 7 months, some of the growth plates will close on time while others that close later will be delayed. This can result in an increase level of stress on not only the joints (resulting in arthritis) but can also affect the tendons and ligaments. In turn, you may increase your risked of damage to the knees and elbows, predisposing your dog to torn ACL (anterior cruciate ligaments) and the like.