The American Mastiff is a large, powerful dog with a wide, heavy, rectangular-shaped head and a powerfully muscular build. The breed has a deep, rounded chest and well-sprung ribs. Their limbs are well-built, straight, and well-muscled, and their burly necks are thick and slightly arched. American Mastiffs have a long tail that reaches the hocks, and a pair of high set ears that are semi-round in shape. Their medium-sized muzzle is well-proportioned and features a black nose. American Mastiffs have teeth that close in a scissors bite and dark, amber-colored eyes. American Mastiff puppies are born darkly colored, and as they get older they become lighter. The breed’s coat can vary slightly in color, but is usually a light fawn that may or may not have some white markings.
American Mastiffs make excellent family pets as they are terrific with children and hopelessly devoted to their owners. They are dignified, mellow, calm, and quiet. While American Mastiffs are very protective, they are never aggressive. Rather, they make excellent watch dogs and only attack if their families (especially children) are in danger. American Mastiffs are social, wise, and gentle with people, and they are very patient with small children and other animals.
Part of the reason the American Mastiff was bred was to deal with some of the health issues the English Mastiff has. Breeders argue they had success with that, English Mastiff breeders say they did not. Being a recent development it is hard to say who is correct as yet, more time is needed. Issues to be aware of that the English Mastiff faces includes skeletal growth abnormalities, bloat, arthritis, breathing problems, lameness, eye problems, joint dysplasia, heart problems, skin problems, hypothyroidism and bladder problems.
Like most giant breeds diet should be formulated for a large to giant breed with moderate to high exercise requirements. You should consult your veterinarian or professional nutritionist for advice on what to feed your American Mastiff and the correct portion sizes. Their dietary needs will change as they grow from puppyhood to adulthood and senior age. Stay on top of these nutritional requirements, suggested food diet consists of fruit, vegetables, raw chickens whole raw eggs as the shell's are high in natural calcium (never feed cooked!) and a high end kibble, also a joint aid supplement is recommended, not forgetting 10% bones.