Inbreeding and family index selection for prolificacy in pigs
Inbreeding and family index selection for prolificacy in pigs
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猪繁殖力的近交和家系指数选择
DOI：
10.1017/s0003356100003135
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发表时间：
1988
期刊：
影响因子：
--
通讯作者：
M. T. Dobao
中科院分区：
文献类型：
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作者：
M. Toro;L. Silió;J. Rodrigáñez;M. T. Dobao
已提出使用家系选择指数作为提高猪繁殖力的一种有前景的选择方法。根据选择计划，使用来自母猪以及母猪和父本的亲属（全同胞和半同胞）的信息，预测每代每窝最多 0-50 头猪的反应。为了在有限规模的种群中测试该方法，使用五个不同的家族选择指数（Id、Ifd、Ihd、Ifs、Ihs），通过模拟研究了选择反应率和近交累积，在选定的牛群（由 10 头公牛和 100 头母牛组成）中的 10 代。有两个明显的不良特征：(a) 指数的标准差低于预期； (b) 近亲繁殖的增加是没有选择的情况下预期的三倍。当假设具有显性的遗传模型时，随着家系指数的复杂性降低每代的选择反应率，这两种效应都会增加到接近 0·20 头仔猪的值，类似于使用基本指数 (Id) 获得的值。还介绍了近亲繁殖对伊比利亚猪的三个品系的繁殖性状影响的一些结果。对 4657 窝仔猪数据的多元回归分析表明，母猪或同窝近交系数每增加 10%，活产仔猪数就会减少 0·14 至 0·35 头。
The use of family selection indices has been proposed as a promising selection method for increasing prolificacy in pigs. Responses of up to 0-50 pigs per litter per generation are predicted from selection programmes using information from the dam and from relatives (full and half-sibs) of the dam and sire. In order to test this method in populations of finite size, the rates of selection response and the accumulation of inbreeding have been studied by simulation along 10 generations in a selected herd of 10 sires and 100 dams using five different family selection indices (Id, Ifd, Ihd, Ifs, Ihs). Two undesirable features were evident: (a) the standard deviations of indices were lower than those expected; and (b) the increase of inbreeding was up to three times that expected without selection. Both effects increased with the complexity of the family index reducing the rates of selection responses per generation, when a genetic model with dominance was assumed, to values close to 0·20 piglets, similar to those obtained with the basic index (Id). Some results of inbreeding effects on reproductive traits in three strains of an old closed herd of Iberian pigs are also presented. Multiple regression analysis of data from 4657 litters indicated a decrease in the number of live born ranging from 0·14 to 0·35 piglets per 10% increase in dam or litter inbreeding coefficient.