University of Khartoum

Genetic And Environmental Factors Affecting Friesian Reproductive Performance In Khartoum State, Sudan

Genetic And Environmental Factors Affecting Friesian Reproductive Performance In Khartoum State, Sudan

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Title: Genetic And Environmental Factors Affecting Friesian Reproductive Performance In Khartoum State, Sudan
Author: Omar,Romaz Mohamed Ahmed
Abstract: This study was conducted to investigate the reproductive performance and to estimate some genetic and phenotypic parameters of five traits in Holstein Friesian cattle under Sudan conditions. The data was obtained from the dairy farm of Azaheir Company for Aِِgriculture and Animal Production at El Bageir. The data used encompassed the first five lactations in 4784 records on 2998 cows covering the period from 1982 to 1998. The data was cleaned by removing errors and outliers and subjected to statistical analysis using Harvey’s (1990) least- squares computer programme. The least squares mean for age at first calving was 28.98 ± 0.35 months, calving interval 14.74 ±0.13l months, open period 131.7 ± 2.08 days, number of service per conception 2.36 ± 0.21 and reproductive efficiency 80.797 ± 0.614%. The analysis of variance shows that sires had a highly significant effect (p< 0.01) on age at first calving, number of services per conception and reproductive efficiency. It was found to have a significant effect (P < 0.05) on calving interval and open period. Yearseasons of birth of cows had a highly significant effect (p< 0. 01) on age at first calving. Also, the effect of year-seasons of calving had a highly significant effect (p<0.01) on calving interval,open period and reproductive efficiency. The effect of parity number on calving interval and reproductive efficiency had highly significant (p<0.01), while it was not significant (P >0.05) on open period and number of services per conception. Heritabilites were estimated by parternal half-sib analysis as described by Becker (1975). The estimates were 0.092 ± 0.021 for age at first calving, 0.008 ± 0.005 for calving interval, 0.004 ± 0.005 for open period, 0.100 ± 0.017 for number of services per conception and 0.057 ± 0.011 for reproductive efficiency. Genetic, Phenotypic and environmental correlations were estimated by paternal analysis of variance and covariance (Becker, 1975). I There were negative genetic correlations between age at first calving and reproductive efficiency (-1.000±0.370), calving interval and open period (-0.406±0.541), calving interval and number of services per conception (0.705±0.286) and number of services per conception and reproductive efficiency (-0.956±0.121). There are positive correlations between calving interval and reproductive efficiency (0.637±0.3080), open period and number of services per conception (0.791±0.550) and open period and reproductive efficiency (0.706±0.551). The genetic correlations between age at first calving and calving interval, open period were not estimable. The phenotypic correlation ranged from positive estimates between age at first calving and calving interval (0.052), age at first calving and open period (0.054) and calving interval and open period( 0.829) to negative estimates between age at first calving and reproductive efficiency (-0.994), and calving interval and number of services per conception (-0.043), calving interval and reproductive efficiency (-0.032 ) , open period and number of services per conception(-0.039 ), open period and reproductive efficiency(-0.024)and number of services per conception and reproductive efficiency (- 0.468). The environmental correlations were negative between age at first calving and reproductive efficiency (-0.993), calving interval and reproductive efficiency (-0.078), number of services per conception and reproductive efficiency (-0.399), open period and reproductive efficiency (-0.05) and open period and calving interval (-0.014). There are positive environmental correlations between calving interval and open period (0.839) and calving interval and number of services per conception (0.001). The environmental correlations between age at first calving and calving interval, open period and number of services per conception were not estimable.
URI: http://hdl.handle.net/123456789/8241
Date: 2007


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