(1)揭露有害基因; (2)保持優(yōu)良個體血統(tǒng); (3)提高畜群的同質(zhì)性; (4)固定優(yōu)良性狀; (5)提供試驗動物
(1)生長發(fā)育及產(chǎn)肉性狀 (2)產(chǎn)奶性狀 (3)繁殖性狀 (4)役用性狀 (5)體型外貌性狀