Nutricula Magazine "The Science of Longevity Journal"
Nutrition and Canine Skeletal Health
by J.Daryll Chester
The important role that nutrition plays in skeletal health in dogs of all sizes and breeds is complex. Many credible studies indicate that what you feed, both in quantity and quality, has a major effect on the developmental health and wellness of your pet’s skeletal growth and health.
A Balanced Whole Food Diet Can Make a Big Difference-
The role of nutrition in developmental skeletal health of young pets is complex. Rate of growth, food consumption, breed-specific diets, non-processed nutrients, and feeding methods have all been proven to be important. Large breeds are more susceptible to problems because of their accelerated growth rate and their requirements for specific nutrients from bio-available sources, (i.e., whole food/non-processed food).
Overconsumption of processed food, over-supplementation, and nutrient-deficient diets all increase the frequency of developmental bone disease in large dogs. Energy, protein and calcium are of the greatest concern.
Young, growing dogs fed commercially processed foods are at more risk, but problems associated with dietary excess are equally likely, especially if a processed food is supplemented with the wrong amount of minerals and vitamins. Most commercially made pet food subscribe to the “one formula fits all” breed theory. This approach is not only wrong but puts you and your pet both at risk for nutrient deficiencies. This, in turn, causes you to “guess” which nutrients to supplement your pet with, and how much of the supplement to add to the diet.
Protein
Protein excess has not been shown to negatively affect calcium metabolism and/or skeletal development in dogs. Protein deficiency, however, has more impact on the developing skeleton. The minimum adequate level of dietary protein depends on the breed, age, digestibility, the amino acid make-up, and their availability from protein sources. Commercial growth pet food should contain at least 28% or greater animal meat protein; (all protein is not created equal). Not only do dietary protein requirements decrease with age, these requirements differ from breed to breed. For instance, an English Mastiff, Irish Wolf hound, and a Golden Retriever have unique individual requirements for all nutrients including protein and calcium.
Calcium
The level of calcium in the diet, not the imbalance in calcium/phosphorus ratio, influences skeletal development. Young, large breed dogs fed a food containing excess calcium (3.3%), with either normal phosphorus (0.9%), or high phosphorus (3% to maintain a normal calcium/phosphorus ratio), had significantly increased incidence of developmental bone disease. These young dogs are unable to protect themselves against the negative effects of calcium excess. High calcium intake increased the frequency and severity of osteochondrosis.
Traditionally, puppies on commercially processed foods are switched from growth formulas to maintenance formula foods to avoid calcium excess and skeletal disease. However, because most maintenance foods have much lower energy density than growth formulas, the puppy must consume more food/volume to meet its energy requirement. Doing so can lead to obesity and other health related issues. If the calcium levels are similar between the two foods, the puppy will actually consume more calcium when fed the maintenance food.
For example: In the case of switching an 18-week-old, 35 lbs. male German Shepherd puppy from a growth formulated food, containing, on an as fed basis, 4.0 kcal/g metabolizable energy and 1.35% calcium (1.75% for dry food), to a maintenance formulated food containing the same amount of calcium, but at a lower, 3.2 kcal/g energy density, the puppy would require approximately 1,600 kcal per day. In order to meet this energy need, the young dog would have to consume approximately 400g of the growth formulated food (containing 5.4g of calcium), vs. 650g of the maintenance formulated food (containing approximately 6.7g of calcium).
Energy
The energy needs for an individual dog depends on their age, breed, lifestyle, neuter status, and stress level of the environment the puppy lives in. On average, growing puppies require twice as much dietary energy as an adult for body maintenance, activity, and growth. The need for good nutrition is greatest right after birth, after weaning from the mother, and decreases as the dog reaches maturity. Each breed (and certain individual’s rate of decline), are unique. Rapid growth in large breed dogs increases the risk of skeletal disease such as Panosteitis. Excessive dietary energy may support a growth rate that is too fast for proper skeletal development; this results in a higher frequency of skeletal abnormalities in large breed dogs. Because fat has twice the caloric density of protein or carbohydrate, dietary fat is the primary contributor to excess energy intake.
Excess energy leads to rapid growth. Nutrition energy in excess of a puppy’s needs will be stored as body fat. Maintaining appropriate body condition during growth not only avoids excess body fat storage, but also helps control excess growth rate.
Limiting the intake of food in order to maintain a lean body condition will not impede a dog’s ultimate genetic potential, overall health, or growth. It will only reduce food intake, fecal production, obesity, and lessen the risk of skeletal disease.
Contributing Nutrients
All nutrients require other contributing nutrients in order to complete their assigned job. Too much or too little of either complementary nutrient and the nutrient/gene-interaction with not function properly. Vitamin D helps to regulate calcium metabolism which affects skeletal development in dogs. The vitamin D metabolites aid in the absorption of calcium and phosphorus from the digestive system, increase bone cell activity, and influence endochondral ossification and calcium excretion. Unlike other omnivores, most breeds/subspecies of dog are dependent on dietary Vitamin D sources from plants (Vitamin D2), and/or animals (Vitamin D3). Because the way most commercially pet foods are formulated, they contain from 2 to 10 times the AAFCO recommended amounts of Vitamin D. This imbalance is where many dietary problems may start.
Excess Vitamin D can cause hypercalcemia, hyperphosphatemia, anorexia, polydipsia, polyuria, vomiting, muscle weakness, generalized soft tissue mineralization, and lameness.
In growing dogs, supplementation with Vitamin D can markedly disturb normal skeletal development due to increased calcium and phosphorus absorption. This is a good example of why many dietitians and nutritionists caution pet owners about using supplements with out the aid of a professional.
The trace minerals, zinc and copper, are involved in normal skeletal development. Copper deficiency in dogs has also been associated with poor hair pigmentation, hyperextension of the distal phalanges, and weakening of the liver, kidney, and heart muscle.
Canine Hip Dysplasia
Canine hip dysplasia (CHD) is the most frequently encountered orthopedic disease in veterinary medicine. The actual number of cases is estimated to be in the millions. This extremely common heritable disorder of large and giant-breed dogs can be influenced by nutrition during growth. Early developmental findings of CHD, including joint laxity and coxofemoral anatomical changes, have been documented within 4 weeks of birth. Rapid weight gain in Newfoundland and German Shepherd dogs during the first 60 days after birth has been associated with CHD at a later age.
The importance of this early, influential time period was demonstrated in a study comparing cesarean-section, hand-reared puppies to vaginal birth, bitch-fed puppies. Cesarean section and hand rearing markedly reduced growth and the incidence of CHD in these puppies. Conversely, vaginally born, bitch-fed puppies that grew “optimally” or somewhat “suboptimally” had a higher incidence of CHD. The period from 3 to 8 months of age is important in the development of CHD, with the first 6 months generally regarded as the most critical.
Electrolyte Balance and CHD
The control of dietary electrolytes has been proven to work as a preventative for CHD. We associate the dietary anion gap (DAG) with the radiographic changes of subluxation in the coxofemoral joints in several canine breeds. The slowed progression of subluxation was also observed in dogs fed a food with a reduced DAG from 35 to 45 weeks of age.
Hip joint laxity was determined using the Norberg hip score computed from radiographs. The balance of anions and cations in the food (specifically sodium, potassium, and chloride), influence the electrolytes and osmolality in joint fluid. The joint fluid of dysplastic dogs has higher osmolality and is increased in volume when compared to that of the disease-free hips from dogs of the same breed. The changes in osmolality and fluid volume could be a result rather than a cause of CHD.
Canine Panosteitis
Canine panosteitis is a disease that affects only large or giant breeds, most often, the Rottweiler, Newfoundland, and German shepherd, although it has been reported even in the Bassett hound, Scottish terrier, Great Dane, St. Bernard, Doberman pinscher, German shorthaired pointer, Irish setter, Airedale, golden retriever, Labrador retriever, Samoyed, and the miniature schnauzer. Males are affected more commonly than females, (reported range 67% to 84%). The disease cycle in the long bones of males is more predictable and repeatable. The female usually has her first episode in association with her first estrus.
Studies have shown nutrition, particularly protein and fat concentrations in the diet, have an impact on the incidence of this disease. My clinical experience has led me to believe Pano is a multifactorial disease that has several different causes, including viral, genetic, and nutritional causes.
Conclusion
In the evaluation of feeding methods and body condition scoring (regardless of a food’s nutrient profile and how it is fed), the ultimate measurement of appropriate intake is the physical condition of the young dog. The only way to reduce the potentially harmful nutritional risk factors that may affect skeletal development is to assess the body condition and to adjust the amounts fed; this will ensure lean, healthy growth. We recommend that “at risk puppies” be evaluated at least every 2 weeks.
Large breed dogs are the most susceptible to developmental skeletal disease. Genetics, environment, and nutrition play key roles. Nutritionally, the rate of growth, food consumption, specific nutrients, and feeding methods influence our ability to optimize skeletal development and minimize skeletal disease. Maximizing the growth rate in young, growing puppies does not correlate to maximum genetic adult size. It does, however, increase the risk of skeletal disease. The growth phase of 3 to 8 months, and the phases after weaning, are vital to ultimate skeletal integrity. The large breeds may be limited in their ability to cope with excesses of minerals such as calcium.
Deficient nutrition and overconsumption of supplements increases the frequency of developmental bone disease in large dogs. Energy, protein, and calcium are the nutrients of greatest concern. Often, owners feeding highly palatable, energy-dense growth foods switch to maintenance type foods in an attempt to reduce developmental disorders. As shown earlier, this practice may worsen total calcium intake. It is not only important to feed “species-appropriate” food, but to feed “breed-specific” whole food appropriately as well.
Nutritional management alone will not completely control developmental bone diseases, but skeletal diseases can be influenced during growth by feeding technique and nutrient profile. Dietary deficiencies and excess are major concerns when feeding a “one formula fit all breeds” commercial pet food even in the specific stages of development, (i.e., puppy, growing dogs, adult, and senior formulations). The potential for harm is in both deficient nutrition and in excessive supplementation.
For more information, a dietary consultation and/or a custom individual diet w/food contact me at Pet Nutrition Systems: www.petnutritionsystems.com/#!consultation-service/c5w7 or call 570.266.1224
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