We estimated genetic parameters in Landrace and Large White pig populations for litter traits at farrowing (total number born, number born alive, number stillborn, total litter weight at birth (LWB), and mean litter weight at birth) and those at weaning (litter size at weaning (LSW), total litter weight at weaning (LWW), mean litter weight at weaning (MWW), and survival rate from farrowing to weaning). We analyzed 65,579 records at farrowing and 6,306 at weaning for Landrace, and 52,557 and 5,360, respectively, for Large White. Single-trait and two-trait repeatability animal models were exploited to estimate heritability and genetic correlation respectively. Heritability estimates of LSW were 0.09 for Landrace and 0.08 for Large White. Genetic correlations of LSW with MWW were -0.43 for Landrace and -0.24 for Large White. Genetic correlations of LSW with LWW and LWB ranged from 0.5 to 0.6. The genetic correlation of MWW with LWW was positive, but that with LWB was negligible. The results indicate that utilizing LWW or LWB could improve LSW efficiently, despite the antagonistic genetic correlation between LSW and MWW.

中文翻译：

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长白猪和大型白猪产仔与断奶仔猪性状的遗传关系。

我们估算了分娩时产仔性状的长白和大型白猪种群的遗传参数（出生总数，活产数量，死产数量，出生时总产仔体重（LWB）和出生时平均产仔体重）和断奶时（产仔数）的遗传参数断奶时的大小（LSW），断奶时的总垫料重量（LWW），断奶时的平均垫料重量（MWW）以及从分娩到断奶的成活率）。对于分娩，我们分析了分娩时的65579条记录和断奶时的6306条记录，对于大白猫，我们分别分析了52557条和5360条记录。利用单性状和两性状可重复性动物模型分别评估遗传力和遗传相关性。LSW的遗传力估计值对于长白猫为0.09，对于大白猫为0.08。LSW与MWW的遗传相关性（长白种）为-0.43，大白种为-0.24。LSW与LWW和LWB的遗传相关性介于0.5到0.6之间。MWW与LWW的遗传相关呈正相关，而与LWB的遗传相关可忽略不计。结果表明，尽管LSW和MWW之间存在拮抗的遗传相关性，但利用LWW或LWB可以有效地改善LSW。