Each species of animal with which we concern ourselves in animal science is constructed according to a fixed plan. Therefore, we consult a textbook on the anatomy of the bovine and have confidence that it applies to all cattle. There are variations, of course, due to differences in genetics, nutrition, age, sex, and even disease. However, the two basic tissues of bone and muscle are always present in the same general pattern. This constancy of structure or organization of tissues is of great value to us in the evaluation of cattle both alive and dead.