Puppies, compared to the pups of other mammals, have a lower degree of bone mineralization. Puppies of large and giant dog breeds are less developed at birth compared to smaller breeds and for this reason are more prone to development of orthopedic diseases during periods of rapid growth. The growth and development of the skeletal system and bone mineralization is an important physiological process that is regulated by a number of hormonal factors, which are influenced by the nutrients from the diet. Additionally, diet is a major source of macronutrients that enable the growth and development of the growing dogs. The energy requirements depend on their growth phase and development. These are all reasons why it is necessary to provide balanced diet especially during the rapid growth phase with the special emphasis on giant breeds because of the speed of their growth. During periods of rapid growth, puppies should be fed a limited amount of energy, using meal restricted feeding regime, based on their body condition score and growth phase. A gradual increase in body weight is the goal during growth phase until tissue development is complete. It is important to note that dogs of large and giant breeds reach adult mass much later than small breeds. Excess weight and rapid growth can lead to pathologies of the skeletal system such as elbow and hip dysplasia, or abnormalities in their position. For this reason it is important to stress that the control of food intake and energy supply in these breeds is of utmost importance. In addition, to ensure optimal growth and development of puppies, it is important to monitor and assess body condition score (BCS). The emphasis of the assessment refers to the rapid growth phase, but it should be used with caution as the BCS scale is validated for adult animals. The goal is to achieve moderate growth intensity rather than maximum to avoid undesirable consequences. The adult bodyweight will not be dependent on the intensity of growth. Additionally, minerals and vitamins in the diet play an extremely important role in bone growth and development. One of the most important elements that affects the physiological process of bone growth and mineralization is calcium. Metabolism of calcium is regulated by calciotropic hormones: PTH, vitamin D and calcitonin, whose function is crucial in the process 48 of bone growth and remodelling. If there is a deficiency or excess of calcium in the diet, it could lead to poor growth, changes in bone mineralization, increased bone resorption, hyperparathyroidism, panosteitis, radius curvus syndrome or elbow dysplasia and hip dysplasia. Due to sensitive mineral and vitamin balance and small margin for error, supplements in puppies are not recommended, and are in fact contraindicated, if the complete and balanced diet appropriate for its age and breed is fed.