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首页> 外文期刊>Reproduction in Domestic Animals >Sexual Precocity of Nellore Bulls that are Offspring of Super Precocious, Precocious and Normal Cows in Extensive Farming Conditions
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Sexual Precocity of Nellore Bulls that are Offspring of Super Precocious, Precocious and Normal Cows in Extensive Farming Conditions

机译：广泛养殖条件下的超早熟，早熟和普通母牛后代内罗尔公牛的性早熟

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Contents The objective of this work was to verify that mothers classified as super precocious (M1) and precocious (M2) produce more precocious bulls than females classified as normal (M3). This study included 21186 animals with an average age of 21.29 +/- 1.77months that underwent a breeding soundness evaluation from 1999 to 2008. Of these animals, 2019, 6059 and 13108 were offspring of M1, M2 and M3 females, respectively. In the breeding soundness examination, the animals were classified as sound for reproduction, sound under a natural mating regime, unsound for reproduction and discarded. To compare the averages obtained for each category of mother within the individual breeding soundness classes, a chi-square test with a 5% error probability was used, considering the effects of year and month of birth and farm. For the three classes of mothers (M1, M2 and M3), 67.26, 67.22 and 64.16% of bull calves were considered sound for reproduction and 19.71, 19.46 and 21.90% were considered unsound for reproduction, respectively. There was no difference in the frequency of animals that were sound for reproduction under the natural breeding regime between the three classes of mothers (8.87, 9.31 and 9.19%, respectively). There was a difference between the numbers of precocious and normal females that were discarded, with frequencies of 4.01 and 4.75%, respectively (p<0.05). There were differences in year and month of birth and farm between super precocious and precocious cows in relation to the breeding soundness classification of the animals. It was concluded that the bull offspring of super precocious and precocious cows presented a higher percentage of approval in the breeding soundness examination than the bull offspring of normal cows, demonstrating that the selection for precocity of females has contributed to an increase in the sexual precocity of the herd in relation to the sexual maturity of bulls
机译：内容这项工作的目的是验证被分类为早熟（M1）和早熟（M2）的母亲比被分类为正常（M3）的雌性产生更多的早熟公牛。这项研究包括21186只动物，平均年龄为21.29 +/- 1.77个月，从1999年到2008年进行了繁殖稳健性评估。在这些动物中，2019年，6059和13108分别是M1，M2和M3雌性的后代。在繁殖稳健性检查中，将动物分类为繁殖声音，自然交配状态下的声音，不繁殖声音并丢弃。为了比较各个育种稳健性类别中每种母亲类别的平均值，考虑了出生年份和月份以及农场的影响，使用了具有5％错误概率的卡方检验。对于这三类母亲（M1，M2和M3），公牛犊的繁殖率分别为67.26％，67.22％和64.16％，繁殖的声音不佳的分别为19.71％，19.46％和21.90％。三类母亲之间在自然繁殖制度下可繁殖的动物的频率没有差异（分别为8.87％，9.31％和9.19％）。被丢弃的早熟雌性和正常雌性的数量之间存在差异，频率分别为4.01和4.75％（p <0.05）。早熟和早熟奶牛的出生年份和月份以及农场存在差异，这与动物的繁殖稳健性分类有关。结论是，超早熟和早熟母牛的公牛后代在繁殖稳健性检查中的认可率要比正常母牛的公牛后代高，这表明雌性早熟的选择促进了雌性早熟的增加。与公牛性成熟有关的畜群

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