Instituto de Ciencia y Tecnología Animal, Universidad Politécnica de Valencia, 46071 Valencia, Spain.
J Anim Sci. 2011 Oct;89(10):2981-7. doi: 10.2527/jas.2011-3906. Epub 2011 May 27.
The aim of this work was to evaluate the response to 10 generations of selection for ovulation rate. Selection was based on the phenotypic value of ovulation rate, estimated at d 12 of the second gestation by laparoscopy. Selection pressure was approximately 30%. Line size was approximately 20 males and 80 females per generation. Traits recorded were ovulation rate at the second gestation, estimated by laparoscopy as the number of corpora lutea in both ovaries; ovulation rate at the last gestation, estimated postmortem; ovulation rate, analyzed as a single trait including ovulation rate at the second gestation and ovulation rate at the last gestation; right and left ovulation rates; ovulatory difference, estimated as the difference between the right and left ovulation rates; litter size, estimated as the total number of kits born and the number of kits born alive, both recorded at each parity. Totals of 1,477 and 3,031 records from 900 females were used to analyze ovulation rate and litter size, respectively, whereas 1,471 records were used to analyze ovulatory difference, right ovulation rate, and left ovulation rate. Data were analyzed using Bayesian methodology. Heritabilities of ovulation rate, litter size, number of kits born alive, right ovulation rate, left ovulation rate, and ovulatory difference were 0.16, 0.09, 0.08, 0.09, 0.04 and 0.03, respectively. Phenotypic correlations of ovulation rate with litter size, number of kits born alive, and ovulatory difference were 0.09, 0.01, and 0.14, respectively. Genetic correlations of ovulation rate with litter size and with number of kits born alive were estimated with low accuracy, and there was not much evidence for the sign of the correlation. The genetic correlation between ovulation rate and ovulatory difference was positive (P = 0.91). In 10 generations of selection, ovulation rate increased in 1.32 oocytes, with most of the response taking place in the right ovary (1.06 oocytes), but there was no correlated response on litter size (-0.15 kits). In summary, the direct response to selection for ovulation rate was relevant, but it did not modify litter size because of an increase in prenatal mortality.
本研究旨在评估对排卵率进行 10 代选择的反应。选择基于排卵率的表型值，通过腹腔镜在第二妊娠期第 12 天估计。选择压力约为 30%。每一代的雄性大约 20 只，雌性大约 80 只。记录的特征包括第二妊娠期的排卵率，通过腹腔镜估计为两个卵巢中黄体的数量；最后一次妊娠期的排卵率，死后估计；排卵率，作为一个单一特征进行分析，包括第二妊娠期的排卵率和最后一次妊娠期的排卵率；左右卵巢的排卵率；排卵差异，估计为左右卵巢排卵率之间的差异；窝产仔数，估计为每次产仔的总产仔数和活产仔数。使用 900 只雌性的 1477 个和 3031 个记录分别分析排卵率和窝产仔数，而使用 1471 个记录分析排卵差异、右卵巢排卵率和左卵巢排卵率。使用贝叶斯方法进行数据分析。排卵率、窝产仔数、活产仔数、右卵巢排卵率、左卵巢排卵率和排卵差异的遗传力分别为 0.16、0.09、0.08、0.09、0.04 和 0.03。排卵率与窝产仔数、活产仔数和排卵差异的表型相关性分别为 0.09、0.01 和 0.14。排卵率与窝产仔数和活产仔数的遗传相关性估计精度较低，并且相关性的符号没有太多证据。排卵率与排卵差异的遗传相关性为正（P=0.91）。在 10 代的选择中，排卵率增加了 1.32 个卵母细胞，其中大部分发生在右卵巢（1.06 个卵母细胞），但窝产仔数没有相关反应（-0.15 只）。总之，对排卵率的直接选择反应是相关的，但由于产前死亡率的增加，并没有改变窝产仔数。
