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Journal of Animal Science and Biotechnology

, 8:56

First Online: 01 July 2017Received: 16 December 2016Accepted: 08 June 2017

Abstract

BackgroundThe objective of the present study was to estimate covariance components of female fertility traits in Chinese Holsteins, considering fertility traits in different parities as different traits. Data on 88,647 females with 215,632 records parities were collected during 2000 to 2014 from 32 herds in the Sanyuan Lvhe Dairy Cattle Center, Beijing, China. The analyzed female fertility traits included interval from calving to first insemination, interval from first to last insemination, days open, conception rate at first insemination, number of inseminations per conception and non-return rates within 56 days after first insemination.

ResultsThe descriptive statistics showed that the average fertility of heifers was superior to that of cows. Moreover, the genetic correlations between the performances of a trait in heifers and in cows were all moderate to high but far from one, which suggested that the performances of a trait in heifers and cows should be considered as different but genetically correlated traits in genetic evaluations. On the other hand, genetic correlations between performances of a trait in different parities of cows were greater than 0.87, with only a few exceptions, but variances were not homogeneous across parities for some traits. The estimated heritabilities of female fertility traits were low; all were below 0.049 except for interval from calving to first insemination. Additionally, the heritabilities of the heifer interval traits were lower than those of the corresponding cow interval traits. Moreover, the heritabilities of the interval traits were higher than those of the threshold traits when measuring similar fertility functions. In general, estimated genetic correlations between traits were highly consistent with the biological categories of the female fertility traits.

ConclusionsInterval from calving to first insemination, interval from first to last insemination and non-return rates within 56 days after first insemination are recommended to be included in the selection index of the Chinese Holstein population. The parameters estimated in the present study will facilitate the development of a genetic evaluation system for female fertility traits to improve the reproduction efficiency of Chinese Holsteins.

KeywordsChinese Holsteins Female fertility Genetic correlation Heritability AbbreviationsAI-REMLAverage information-restricted maximum likelihood

AISNumber of inseminations per conception

CRConception rate at first insemination

DODays open

ICFInterval from calving to first insemination

IFLInterval from first to last insemination

MACEMultiple across-country evaluation

NRR56Non-return rate within 56 days after first insemination

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Autor: Aoxing Liu - Mogens Sandø Lund - Yachun Wang - Gang Guo - Ganghui Dong - Per Madsen - Guosheng Su

Fuente: https://link.springer.com/







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