Genetic and Phenotypic Parameters among Crossbred Cows in the University of Khartoum Farm

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Date
2001
Authors
Manal Mohamed Ahmed Hamza
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Publisher
University of Khartoum
Abstract
The present study was conducted to investigate the genetic and non-genetic influences on reproductive and productive traits and to estimate the genetic parameters in the crossbred herd of the University of Khartoum Farm. The study included records of 215 crossbred cows (Friesian x Kenena and Friesian x Bunana), covering the period 1971-1999. The least squares means for the first parity traits (age first calving, calving interval, total lactation milk yield, daily milk yield, lactation length and dry period) were 43.78±1.19 months 451.72 ±7.96 days, 2521.88±10175 kg, 6.47±0.26 kg, 387.54±8.52 days and 102.26 ±5.21 days, respectively. The results showed that the Friesian blood percentage had a significant effect on calving interval lactation milk yield, daily milk yield, lactation length and dry period. While the year-season of calving had no significant effect on all traits expect age at first calving (P<0.001). Heritibilities were estimated by paternal half sib analysis and the estimates were 0.122±0 147, 0.019±0.075, 0.096±0.9 I and 0.044±0.077 for calving interval, dry period, total milk yield and daily milk yield. Genetic, phenotypic and environmental correlations were estimated by paternal half sib analysis of variance and covariance. The genetic correlations were 0.016±1.146 for age at first calving and lactation milk yield, 1.315±0.662 for lactation milk yield and daily milk yield, 1.143±1.612 for lactation milk yield and dry period, 0.516±1.33 for lactation milk yield and calving interval, 1.034±0.80 for dry period and calving interval. The phenotypic correlations between the same traits were 0.155, 0.896, 0.291, 0.124 and 0.905, respectively. Likewise the environmental correlations were 0.251, 0.706, -0.108, -0.059 and 0.829, respectively.
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Keywords
University of Khartoum Genetic Parameters Phenotypic Parameters Crossbred Cows University of Khartoum Farm
Citation
Manal Mohamed Ahmed Hamza, Genetic and Phenotypic Parameters among Crossbred Cows in the University of Khartoum Farm .- Khartoum : University of Khartoum, 2001 .- illus., 28cm., MS.c.