Puppy Nutrition 101
Puppy Nutrition 101 The dog is unique amongst other mammals in that it has the widest range of normal adult body weight within one species. Many breeds will reach 50% of their adult size within 5-6 months. Some breeds will be fully grown by 8-12 months, some 12-18 months, and others 18-24 months. With this incredible range, it’s no surprise that puppyhood is in fact a very sensitive period, and one that we need to get right. Here at My Pet Nutritionist, we are incredibly lucky that we support many owners in choosing the right nutritional plan for their growing puppy. But we thought we’d compile a brief guide to some of the most important things to consider for the growing puppy. Growth and Development After nursing, post-weaning growth is the most nutritionally demanding period in a dog’s life. For large and giant breeds, the length and speed of their growth poses an even higher nutritional demand. By maturity, most dogs will have increased their birth weight by 40-50 times. How amazing is this? But it also poses something to be very conscious of. Physical Growth How are bones formed? Also known as ossification, bone formation is a process where new bone is produced. Look at any large breed and it is clear to see how much new bone needs to be produced from birth to full skeletal maturity. Bone starts as a cartilage model which gets slowly replaced. Osteoblasts are the cells that form new bone. They secrete osteoids. Osteoid tissue is simply unmineralised bone tissue. Soon after the osteoid is laid down,inorganic salts are deposited which forms the hardened material that we know as bone. These inorganic salts include calcium and phosphorus. Bone formation proceeds outwards from ossification centres; short bones tend to have one in the middle whereas long bones typically have three, one at each end and one in the middle. Ossification, or bone formation continues until there is a thin strip of cartilage left at each end of the bone. This is known as the epiphyseal plate, or growth plate in the dog world. When the bone reaches full adult maturity, the cartilage is replaced with bone and“sealed” for want of a better word. It is therefore no surprise that certain minerals are necessary for physical bone growth, along with some vitamins. Calcium is the most abundant mineral in the body; the majority of which is contained in the skeleton. Phosphorus is the next most abundant; also found in bone. Although they have separate functions within the body, being so closely interrelated, they are usually considered together. Calcium is involved in constriction and dilation of blood vessels, nerve impulse transmission, muscle contractions(including the heart), secretion of hormones and blood coagulation. It also plays a role in fluid balance in cells (contributing to homeostasis). A diet grossly inadequate in calcium, results in hypocalcemia. The body will remove calcium from bones to ensure normal cell function in the rest of the body. This leads to weakened bones. Hypercalcemia is a little more uncommon, but it is most often linked with overactive parathyroid gland function. Phosphorus is essential in cell growth and differentiation, energy use and transfer, fatty acid transport and amino acid and protein formation. In general, phosphorus is better absorbed from meat products than plant products. Phosphorus found in meat is mainly in its organic form; in plants it is in the form of phytic acid. Phytic acid impairs the absorption of iron,zinc and calcium and has been linked to mineral deficiencies. It is often referred to as an anti-nutrient. Deficiencies of calcium and phosphorus are unusual, but imbalance is noted. In unbalanced diets, calcium deficiency can develop alongside high levels of phosphorus. Low calcium levels stimulate the release of parathyroid hormone, which increases the production of the active form of Vitamin D. This results in an increased bone reabsorption to restore calcium levels. This eventually leads to bone demineralisation and a loss of bone mass. In dogs, this is more commonly noticed in the mandibles (jaw bones), leading to tooth loss and periodontal disease. Attention is most often paid to the calcium:phosphorus ratio. The note to make is that organic sources of both minerals are slowly and less efficiently absorbed; so, in fresh fed dogs this is less of a concern in terms of excess. Phosphorus found in meat products however is more efficiently absorbed than that found in plants. Findings here Other nutrients relevant to skeletal development include vitamin D, vitamin A, copper, zinc and manganese. Deficiency or excess in these have regularly been linked to abnormal orthopaedic development. But, as we know, it is not just the bones in puppies that grow – it is in fact every part of their body! What do puppies need to grow? Protein Proteins are large, complex molecules composed of hundreds to thousands of amino acids. They are literally the building blocks of the body. Protein is required in the diet to provide a source of amino acids to build, repair and replace body proteins. Proteins in the body have numerous functions. Major structural components of hair, skin, nails, tendons, ligaments and cartilage. Hormones are composed of protein molecules – these include insulin and glucagon which are key to maintaining blood sugar levels. Proteins are found in the blood– for example haemoglobin carries oxygen between the lungs and cells,lipoproteins carry fats throughout the body and transferrin carries iron through the blood. Proteins are also found in the immune system in the form of immunoglobulins to make the antibodies that provide resistance to disease. All proteins are in a constant state of renewal and degradation and during growth (or reproduction) additional protein is needed for the creation of new tissue. High rates of protein synthesis occur in: The production of red and white blood cells Epithelial cells of the skin and those lining the GI tract and pancreas Digestion of Protein Dietary amino acids are absorbed in the gastrointestinal tract, following disruption of their structure. They are then transported