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University of Khartoum (2007)

The Genetics of Reproductive and Productive Performance of Holstein-Friesian Cattle in Khartoum State, Sudan

Ibrahim,Bader Eldean Hassan

Titre : The Genetics of Reproductive and Productive Performance of Holstein-Friesian Cattle in Khartoum State, Sudan

Auteur : Ibrahim,Bader Eldean Hassan

Université de soutenance : University of Khartoum

Grade : Master of Science (MS) in Animal breeding 2007

Résumé
This study was conducted to estimate the effect of some environmental and genetic parameters on reproductive and productive performance of pure Holstein-Friesian cattle at Dairy-Land farm (Azaheir) in Khartoum, State Sudan. The study included 736 Holstein-Friesian cows from 43sires covering the first five lactations during the period from 1984 to 2004 were used in the study. The reproductive characteristics examined were : age at first calving, number of services per conception and calving interval. The productive characteristics examined were : total milk yield and lactation length. The data were subjected to statistical analysis using Harvey’s Least Squares and maximum likelihood analysis. The results showed that the least squares means for age at first calving, number of services per conception, calving interval, total milk yield and lactation length were 29.90±0.72 months, 2.77±0.12, 521.10±18.78days, 3762.29±156.47Kg, and 279.99±1.90 days, respectively. The analysis of variance revealed that the sires of cows birth did not significantly (p>0.05) influence the calving interval and lactation length but, they had a highly significant (p<0.01) effect on age at first calving, number of services per conception and lactation yield. The year-season of calving did not significantly affect (p>0.05) calving interval, lactation yield and lactation length. However, it had a vii highly significant (p<0.01) effect on age at first calving. The parity number did not have a significant (p<0.05) effect on number of services per conception, calving interval, lactation yield and lactation length. Analysis the linear regression showed a highly significant (p<0.01) effect on lactation yield and lactation length but had a significant affect (p<0.05) on calving interval. Genetic, phenotypic and environmental correlations were estimated by paternal half-sib analysis of covariance (Becker, 1975). And the Heritabilities were estimated by paternal half-sib analysis as described by (Falconer, 1996). The estimates were (0.151±0.042), (0.062±0.019), (0.002±0.014), (0.110±0.029), (0.011±0.11) for age at first calving, number of services per conception calving interval, total milk yield and lactation length, respectively

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