University of Khartoum

The Performance of Holstein-Friesian Cattle Under Sudan Conditions

The Performance of Holstein-Friesian Cattle Under Sudan Conditions

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Title: The Performance of Holstein-Friesian Cattle Under Sudan Conditions
Author: ZEIN ELABDEEN, AMANI
Abstract: This study was conducted to investigate the reproductive and productive performance and to estimate some genetic parameters of these traits in Holstein- Friesian cattle at Dairy Land Farm in Sudan. Data of the first four lactations covering the period from 1986 to 2002 was studied and subjected to statistical analyses using Harvey’s least – squares computer programme (1990). The least squares means for age at first calving, calving interval, service period, number of services per conception, lactation milk yield, daily milk yield, lactation length and dry period were 29.762±0.395 months, 433.117±6.699 days, 167.785±7.084 days, 2.348±0.107, 3475.526±78.889 kg , 12.29±0.279 kg , 294.104±3.622 days and 164.075±6.699 days, respectively. The analysis of variance revealed that the sire had a highly significant (P<0.001) effect on number of services per conception, lactation milk yield and daily milk yield. The effect of sire on lactation length was highly significant (P<0.01), and there was a significant (P<0.05) effect of sire on service period. The calving year-season had a highly significant effect (P<0.001) on age at first calving, lactation milk yield , daily milk yield and lactation length. Parity had a highly significant (P<0.001) effect on service period, number of services per conception, lactation milk yield and daily milk yield. It also had a significant (P<0.05) effect on calving interval and dry period. Linear and quadratic regressions on lactation length had a significant (P<0.001) effect on lactation milk yield and daily milk yield. Linear regression on lactation length had a highly significant (P<0.001) effect on calving interval 7 and dry period. It also had a highly significant (P<0.01) effect on service period. Both linear and quadratic regressions on daily milk yield had highly significant (P<0.001) effects on lactation length. Heritabilities were estimated by paternal half-sib analysis as described by (Becker, 1975) and the estimates were 0.098±0.104, 0.047±0.046, 0.51±0.37, 0.032±0.044, 0.130±0.042, 0.123±0.041, 0.172±0.062 and 0.044±0.039 for age at first calving, calving interval , service period, number of services per conception, lactation milk yield, daily milk yield, lactation length and dry period. Genetic and phenotypic correlations were estimated by paternal half-sib analysis of variance and covariance ( Becker, 1975). The genetic correlations were- 0.546±0.139 for age at first calving and lactation milk yield, 0.297±0.047 for calving interval and lactation milk yield, 0.117±0.047 for service period and lactation milk yield, 0.140±0.035 for number of service per conception and lactation milk yield, 0.928±0.047 for lactation milk yield and daily milk yield, 0.615±0.171 for lactation milk yield and lactation length, - 0.79±0.49 for lactation milk yield and dry period, -0.72±0.54 for lactation length and dry period, 0.212±0.004 for lactation length and calving interval and finally 0.56±0.28 for dry period and calving interval. The phenotypic correlations between the same traits were 0.153, 0.192, 0.157, 0.195, 0.887, 0.693, – 0.141, – 0.260, 0.220 and 0.880 respectivel
Description: 109page
URI: http://hdl.handle.net/123456789/7980
Date: 2015-04-01


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