Instituto de Ciencia y Tecnología Animal, Universitat Politècnica de València, P.O. Box 22012, 46071 Valencia, Spain.
Animal. 2019 Nov;13(11):2457-2462. doi: 10.1017/S1751731119001423. Epub 2019 Jun 26.
Rabbit commercial maternal lines are usually selected for litter size (LS) and paternal lines for growth rate (GR). Line OR_LS was selected by ovulation rate (OR) and LS to improve LS more efficiently. In this study, growth traits of line OR_LS were evaluated by estimating the correlated response on weaning weight (WW), slaughter weight (SW) and GR during fattening period as well as their variability (DWW, DSW and DGR, respectively). Data were analyzed using Bayesian inference methods. Heritability estimates were low for growth traits (0.09, 0.13 and 0.14 for WW, SW and GR, respectively) and negligible for growth traits variability (0.01, 0.004 and 0.01 for DWW, DSW and DGR, respectively). Moderate common litter effect ratio (c2; 0.35, 0.28 and 0.27) and low maternal effect ratio (m2; 0.11, 0.05 and 0.01) were obtained for WW, SW and GR, respectively. Both c2 and m2 were lower at slaughter than at weaning. In addition, low common litter effect and negligible maternal effect were observed for growth traits variability. Genetic correlations between LS and both growth traits and their variability were close to zero. Positive genetic correlations were observed between OR and growth traits (0.19, 0.38 and 0.36 for WW, SW and GR, respectively) as well as between OR and growth traits variability (0.35, 0.62 and 0.20 for DWW, DSW and DGR, respectively). Positive correlated responses in both periods were obtained for growth traits, WW, SW and GR (0.037, 0.156 and 0.110 kg, respectively). The correlated response found in growth traits might be due to the positive genetic correlations between OR and these traits. However, selection for OR and LS using independent culling levels did not modify the growth traits variability. Therefore, no negative consequences on growth traits can be expected in current commercial maternal lines.
商业用兔母系通常选择产仔数（LS），父系选择生长速度（GR）。OR_LS 系通过排卵率（OR）和 LS 选择，以更有效地提高 LS。本研究通过估计断奶体重（WW）、屠宰体重（SW）和育肥期生长速度（GR）的相关反应，以及它们的变异性（分别为 DWW、DSW 和 DGR），来评估 OR_LS 系的生长特性。数据采用贝叶斯推断方法进行分析。生长特性的遗传力估计值较低（分别为 WW、SW 和 GR 的 0.09、0.13 和 0.14），生长特性变异性的遗传力可以忽略不计（分别为 DWW、DSW 和 DGR 的 0.01、0.004 和 0.01）。WW、SW 和 GR 的共同窝效应比（c2）分别为 0.35、0.28 和 0.27，母性效应比（m2）分别为 0.11、0.05 和 0.01。WW、SW 和 GR 的 c2 和 m2 在屠宰时均低于断奶时。此外，生长特性变异性的共同窝效应和母性效应均较低。LS 与生长特性及其变异性之间的遗传相关性接近零。OR 与生长特性（分别为 WW、SW 和 GR 的 0.19、0.38 和 0.36）以及与生长特性变异性（分别为 DWW、DSW 和 DGR 的 0.35、0.62 和 0.20）之间存在正遗传相关性。在两个时期，生长特性、WW、SW 和 GR 都获得了正的相关反应（分别为 0.037、0.156 和 0.110 kg）。生长特性的相关反应可能是由于 OR 与这些特性之间存在正遗传相关性。然而，使用独立的淘汰水平对 OR 和 LS 进行选择并没有改变生长特性的变异性。因此，目前商业母系中不会对生长特性产生负面影响。
