Animal agriculture by whichever term you choose-animal science, animal industry,or animal husbandry-can be subdivided into several areas for additional study.One method of subdivision is based on the various biological functions of the animal.It is this approach that has been used to a largh extent in the organization of this book.Those boby functions having a more direct relationspis to the animal's aconomic importance will receive greater emphasis.These important areas include genetics, reproduction,nutrition,disease resistance.and production of food products.