猪品种选育及繁育体系建立的研究

Study on the Establishment of Swine Selection and Breeding Systems

采用完全闭锁的群体继代法对美系长白、大白、杜洛克、汉普夏从24系种猪进行选育，经过10a6个世代的测定与选择，各项性能指标均达育种目标．所选种猪具有高繁殖率、高生长率、高质、高效的特点；母系种猪（长白、大白）有发情明显、温驯、受胎率高、产活仔数多，长白猪平均窝产活仔10．37头，大白猪平均窝产活仔10．86头．21天龄窝质量，长白猪为54．23kg，大白猪为58．81kg．父系公猪生长速度快，测定期最高日增质量为1020g、饲料报酬高、胴体品质好，胸体瘦肉率达到65．30％．杜长大及杜大长杂交组合配套生产的商品猪表现了良好的配合力，165日龄内达90kg．

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.