Veterinarians and pet owners have long been concerned about the various joint disorders that are so common in the giant breeds like Great Danes, Irish Wolfhounds, Bernese Mountain dogs, Saint Bernards and the Newfies. The larger breeds like Rotties, Labs, Goldens, and German Sheperds are also over-represented with conditions like hip dysplasia, elbow dysplasia, osteochondrosis dissecans (OCD) of the shoulders, knee, carpi (wrists) and tarsi (ankles), hypertrophic osteodystrophy (HOD), and panosteitis.
Although genetic factors are the largest, unavoidable contributor to these problems, nutritional interventions during puppyhood can influence and help decrease the incidences of these conditions in predisposed breeds.
Conditions That Affect Large Breed Dogs
Hip dysplasia and elbow dysplasia occur due to growth speed and structure between the bones of the joint.
In hip dysplasia the head of the femur (long bone of the leg) forms incorrectly. The acetabulum, or cup of the pelvis, also forms abnormally or forms abnormally due to the poor fit of the head of the femur.
The same dynamics cause elbow dysplasia. The cup shaped end of the ulna (one of the bones of the forearm) and the spool shape at the end of the humerus (large bone of the upper arm) that fits in the ulnar cup may be malformed or grow differently so the joint does not work smoothly. Often the anconeal process and the coronoid process, which are the points of the cup, will fracture, creating floating pieces that irritate the already malformed joint.
2 – Aconeal Process 3 – Coronoid Process
The end result of both dysplasias is osteoarthritis that worsens with age.
Osteochondrosis dissecans, or OCD, is a growth defect of the bone end-plates under the slippery, articular surface cartilage of a joint. Improper growth and blood supply under this tissue results in dysfunctional articular bone development. The tissue dies and breaks off causing rough divots in the joint that cause pain and lameness. Without surgical intervention osteoarthritis can develop.
OCD of shoulder joint
Hypertrophic osteodystrophy, or HOD, affects the long bones of rapidly growing large and giant breed puppies. Inflammation and swelling of the bone beneath the growth plates in these puppies causes severe joint swelling, pain, lameness, reluctance to move, anorexia, and fever.
Panosteitis is also an inflammatory condition that affects the interior of long bones of the same group of puppies. Improper bone remodeling during the growth period affects bone blood vessels and the resulting inflammation. Joint swelling is uncommon but the symptoms include those similar to puppies affected with HOD.
HOD Radiographic image of panosteitis
The Role of Nutrition
Genetics aside, scientific studies have led to the present conclusion that rapid growth of the long bones in puppies is a risk factor for developing these joint and bone conditions. Rapid bone growth can be caused by two methods; overfeeding and calcium supplementation. Puppies allowed to free-feed or those fed liberal meal portions that exceed their daily caloric needs risk rapid bone growth.
Puppies of these breeds should constantly have their caloric intake adjusted during the growth period, which can be a long as 8-12 months in the large breeds and 15-18 months in the giant breeds. Because calorie information is not required for pet food labeling, veterinarians and owners will need to consult company websites for this information in order to calculate proper ration amount. The key is to keep these puppies growing at a slow, steady rate. Maintaining a body condition score of 4-5 during the growth period will also aid proper growth.
Unlike older dogs, puppies under 6 months of age cannot regulate the amount of calcium that is absorbed from the intestines. Passive absorption of calcium is directly proportional to the amount of calcium in the food or supplements. Studies have demonstrated that excessive calcium promotes rapid bone growth and increases the risk of joint disease and HOD. Elevated blood calcium levels also triggers hormonal changes that decrease re-modeling activity of growing bones and compromises blood supply in bone that promotes panosteitis.
Feeding puppies adult-maintenance food too early is the same as calcium supplementation. Commercial food formulation for calcium is based on the caloric density of food. Adult food is less caloric dense so more of the food is required to meet the caloric needs of puppies. This can result in the consumption of two times the amount of calcium than would be ingested with puppy formulations.
Despite common belief, experiments have failed to support any positive impact supplementation with vitamin C has on these joint conditions.
The bottom line is that large and giant breed puppies should be carefully fed a quality puppy formula until the end of their growth period before being switched to adult formulas. Calcium supplementation should be avoided during this same time period.
Dr. Ken Tudor
Canine Osteochondrosis — Veterinary Medical Clinic
Canine Hypertrophic Osteodystrophy — Carrboro Plaza Veterinary Clinic
Canine Panosteitis — Animal Central
Elbow Dysplasia Manifestations — Wikimedia Commons
Hip Dysplasia — Minnesota Malamute Club