蛋鸡产蛋量早期选择的优化研究

计算分析表明,常规的产蛋量早期选择性状40周龄产蛋数不能准确地反映出个体的实际产蛋能力,选择效率不够理想。本文以不同早期产蛋记录的间接选择效率为主要判别依据,结合考虑与其它重要性状之间的遗传相关,筛选出产蛋量的优化早期选择性状,并对其选择准确性进行了验证。在京白Ⅲ系,筛选出的产蛋量优化记录期为23～40周龄,在Ⅷ系为25～48周龄。计算结果表明,用优化记录期内产蛋数作早期选择可以更有效地改良年产蛋量,提高产蛋中后期的持续性。而且,优化记录期内产蛋数与36周龄蛋重的遗传拮抗作用已显著地减弱(r_A=-0.16),为同时改良产蛋量和蛋重指出了希望。筛选产蛋量优化记录期的实质,是避免性成熟的早晚对估计实际产蛋能力的干扰作用,所以优化记录的起始点应当是在绝大多数个体都开产以后。

OPTIMAL SELECTION FOB EGG PRODUCTION WITH EARLY RECORDS IN LAYERS

It was shown that the conventional selection criterion of egg production (e. g. egg number to 40 weeks of age) could not accurately reflect the actual laying ability of hens and would lead to inefficient selection response. A method to decide the optimal selection criterion of egg production was suggested based on the selection efficiency of segments of early records, as well as the genetic correlations with other economic traits. The optimal criterion in Line 3 of Beijing White Leghorn was egg number from 23 to 40 weeks of age, and in Line 8-egg number from 25 to 48 weeks. It was found that the optimal criterion could increase selection accuracy by 8~11%. The results also indicated that the optimal criterion could more efficiently improve the laying persistency, and showed a much lower genetic antagonism with egg weight at 36 wecks(rA= - 0.16). The essence of optimization was concluded as to avoid the interference of sexual maturity in estimating the actual laying ability, thus the start of the optimal record should be the time when most of hens in flock has commenced laying.