This article discusses 5 key nutrients required for growing puppies and the potential consequences of feeding an unbalanced diet during this key phase.
The growth phase is the most complex and delicate stage of a dog’s life during which a multitude of macro and micro-nutrients are required at specific levels to achieve healthy growth, optimise immune function, minimise potential for obesity, and avoid developmental orthopaedic disease.
Protein is an important nutrient for puppies’ growth, supplying amino acids to build hair, skin, nails, muscles, tendons, ligaments, and cartilage. Immediately after weaning, the protein requirements for growing puppies are the highest; however, it will decrease thereafter. In the growth phase, the required protein level is 22-32% on a dry matter basis to support optimal growth. High-protein intake may contribute to the development of skeletal abnormalities, hip dysplasia, degenerative joint disease, and secondary osteoarthritis in growing puppies. On the other hand, a diet low in protein results in weight loss and delay or cessation of growth. In addition, it is important not to decrease protein level in large dog breeds diet at the same stage as small and miniature breeds since they will continue to grow for a longer period.
Fats are important in the diet for fulfilling energy needs, and supplying essential fatty acids, and are needed for the absorption of certain vitamins. Essential fatty acids maintain the cell structure, manage inflammation, and are necessary for optimal functioning of various organs including eyes and brain. In the growth phase, the required fat level is 10-25% on a dry matter basis. Excessive fat/energy intake results in obesity and developmental orthopaedic disease.
Large-breed puppy foods contain an energy density of 3.5 to 4.0 kcal/g which is lower than the 4.0 to 4.5 kcal/g of regular puppy foods. This reduced-energy level leads to reduced fat deposition and a lower caloric intake in puppies fed free choice. High-fat diets affect levels of insulin-like growth factor-1, whereas diets high in saturated fats increase bone formation.
The calcium level for small to medium breeds ranges from 0.7-1.7% on a dry matter basis. Dietary calcium absorption in puppies after weaning includes passive and active transport. Passive calcium absorption from the gut is directly proportional to dietary calcium intake in puppies from weaning until 6 months of age and represents up to 70% of total calcium uptake. Active calcium absorption is regulated by vitamin D3, parathyroid hormone, growth hormone, and calcitonin and decreases with increasing age in young puppies fed an excess of calcium. Excessive calcium intake is stored in skeletal bone of large-breed puppies, thus increasing the risk of developmental orthopaedic diseases.
Phosphorus in combination with calcium strengthens the skeletal structure of puppies. It is important to maintain the calcium-phosphorus ratio to ensure there is adequate calcium within the bones. In the presence of normal calcium intake, phosphorus absorption is well regulated in young puppies. However, overfeeding puppies with calcium decreases the absorption of phosphorus. Dietary deficiency of phosphorus leads to poor weight gain and reduced growth rate. The phosphorus level for puppies of small to medium breeds ranges from 0.6-1.3% on a dry matter basis.
Vitamin D has a significant role in maintaining the skeletal calcium balance which promotes bone re-absorption and subsequent function of the parathyroid hormone.
In addition, vitamin D regulates gut absorption of calcium and phosphorus and renal excretion or resorption of minerals. Vitamin D deficiency leads to osteomalacia (bone softening) and rickets in all breeds.
Puppies require a minimum of 500 IU of vitamin D per kg of food. Vitamin B complex regulates energy and carbohydrate metabolism, facilitates enzyme function, glucose generation, red blood cell and nervous system function, hormone regulation, immune response, and amino acid metabolism. Vitamin C is an important antioxidant scavenging potentially harmful free radicals in the body and reducing inflammation. Dogs can synthesise vitamin C in their livers, but in some cases, supplementation may offer health benefits.
Vitamin E protects puppies from oxidative damage and is essential for cell function and fat metabolism. Vitamin E deficiency leads to eye and muscle degeneration and reproductive problems. The daily requirement for puppies is 400 IU of vitamin E. Vitamin K activates puppies’ blood ability to clot and they require 0.33 mg of vitamin K for every 1,000 calories.
* References are available upon request.