第五世代
第五世代-
母猪头数300头和400头以上的相比，第五世代的累积选择反应增加有限，近交系数下降速度减低。
When the sow number of breeding population was increased from 300 to 400 above , the cumulative selection response only increased slightly , and the coefficient of inbreeding continued to decrease but at a diminished rate .
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从第四世代起执行这个选择方案，经过第四、第五、第六世代三个世代的选择，使90公斤左右育肥猪的瘦肉率从55.46%提高到56.71%。
Percentage of lean meat of finishers with the weight of 90 kg or so raises from 55.46 to 56.71 % through selection for the fourth fifth and sixth generation .