The quality of animals slaughtered has a big effect on the standard of meat produced. The most important factors are feeding, age, genetics and health status. Efforts have been made to improve meat production and quality by breeding, or to combine the key characteristics by means of crossbreeding. New breeds with improved meat quality and carcass yields and adapted disease resistance can make a significant contribution to improved meat availability for human nutrition. Typical cattle breeds originating from Asia are Brahman and Gyr. These breeds and their crosses are common in most tropical countries around the world. Angus, Charolais, Hereford, Limousin and Simmental are typical European breeds. Also the increasingly popular Japanese Wagyu is a cross of native cattle and European inputs.
Most authorities have considered that the origins of the domestic chicken (Gallus domesticus) were the Red Jungle Fowl of Asia. The present day chickens are larger and more productive than the ancestral Red Jungle Fowl with four basic types: 1) egg type, or Mediterranean; (2) game; (3) meat type; and (4) Bantam. Within these types, there are an estimated 1233 different breeds of chicken that are recognized. Most commercial broilers are hybrid chickens.
A huge number of native pig breeds exist around the world and are well adapted to local conditions. Typical commercial pig breeds are the various landraces (Danish, German, Dutch, Italian, etc.) and the Large Whites in Europe, often crossed with the Pietrain race from Belgium. In Asia, the Beijing Black and the Jinhua pig from China and the Mong Cai from Vietnam are common. Most commercial pigs are crosses or hybrids.