Your large-breed puppy needs the proper nutrients and calories during their growing period in order to support the development of their growing skeletal, nervous, and sensory systems. This can be problematic for puppies this size because excessive calcium or vitamin intake can be detrimental due to their susceptibility to bone and joint issues. Younger puppies require the best protein to develop their own immune systems because they gradually lose the "antibody shield" that comes from their mother's colostrum. Royal Canin® Maxi Puppy is a specially formulated food designed to meet the nutritional requirements of puppies from large breeds. Large-breed puppies that are 2 to 15 months old and should grow to be 26 to 44 kg as adults can use this formula. Vitamins C and E are among the nutrients in this formula that support the puppies' natural defenses while