Study on the Establishment of Swine Selection and Breeding Systems

Breeder pigs including American-lines Landrace, Large White, Duroc, Hampshire and line 24 were selected and bred by systematic ally. Continuing tests of the 6 generations selected in 10 years indicated the pigs accomplished the goals of the breeding program. Breeding pigs showed multifarious charecters, i. e. high prolificacy, fast growth rate and high production efficiency. Dam line breeder swine (Landrace and Large White) exhibited evident estrous signs, tame temperament, high conception rate,large litter size, with live birth averaging 10. 37 and 10. 86, and 21-day litter mass averaging 54. 23 and 58. 81kg, for Landrace and Large White respectively. Fast growth was expressed by sire line boars which achieved maximum daily gain of up to 1020 g during test Peried. In addition the boars also attained good performance regarding to feed conversion efficiency and leannss with lean rate reaching 65. 3%, Commereial pigs produced by cross combinations of Duroc x Landrace x Large White and Duroc x Large White x Landrace expressed high heterosis and took 165 days to reach 90 kg of market mass.