Tag EI-Dein,, M., Hussein, K. (2005). GENETIC AND PHENOTYPIC STUDIES ON MILK PRODUCTION TRAITS OF FRIESIAN COWS IN EGYPT.. Journal of Animal and Poultry Production, 30(10), 5849-5856. doi: 10.21608/jappmu.2005.238048
M. A. Tag EI-Dein,; K. Hussein. "GENETIC AND PHENOTYPIC STUDIES ON MILK PRODUCTION TRAITS OF FRIESIAN COWS IN EGYPT.". Journal of Animal and Poultry Production, 30, 10, 2005, 5849-5856. doi: 10.21608/jappmu.2005.238048
Tag EI-Dein,, M., Hussein, K. (2005). 'GENETIC AND PHENOTYPIC STUDIES ON MILK PRODUCTION TRAITS OF FRIESIAN COWS IN EGYPT.', Journal of Animal and Poultry Production, 30(10), pp. 5849-5856. doi: 10.21608/jappmu.2005.238048
Tag EI-Dein,, M., Hussein, K. GENETIC AND PHENOTYPIC STUDIES ON MILK PRODUCTION TRAITS OF FRIESIAN COWS IN EGYPT.. Journal of Animal and Poultry Production, 2005; 30(10): 5849-5856. doi: 10.21608/jappmu.2005.238048
GENETIC AND PHENOTYPIC STUDIES ON MILK PRODUCTION TRAITS OF FRIESIAN COWS IN EGYPT.
Dept. of Animal breeding, Animal Production Research Institute, Ministry of Agriculture, Egypt.
Abstract
Total of 2860 records from 1st to e" lactations of Friesian cows were used in the present study. Number of sires and the average number of daughters per sire were 231 and 12.4, respectively. These data were used to estimate genetic and phenotypic parameters for total milk yield (TMY), 305 day milk yield (305 DMY) and lactation period (LP). The statistical model included the effect of sire as random effect, month of calving, year of calving and parity as fixed effects and both of cow weight at calving (CW) and age at first calving (AFC) as covariate on milk production traits.
The results obtained could be Summarized as follows:
1- The arithmetic means of TMY, 305 DMY and LP were 4851 kg, 4205kg and 405 day, respectively.
2-Month of calving had significant effect (P< 0.05) on TMY and 305 DrAY and non significant effect on LP.
3- Year of calving had highly significant effect (P, 0.01) on TMY and 305 DMY, while non significant on LP.
4-Parity had highly significant effect (P, 0.01) on ali traits under study.
5- Estimation of partial linear regression coefficients of TMY on CW was positive and highly significant (P, 0.01), and only significant (P, 0.05) for 305 DMY on CW, while, partial quadratic regression coefficients of TMY and 305 DMY on CW were positive and highly significant (P, 0.01), partial quadratic regression coefficients for traits under study of AFC were positive and highly significant (p < 0.01)
6- The sire had highly significant effect (p, 0.01) on TMY and LP, but only significant effect (P, 0.05) on 305 DMY .
7-Heritability estimates ( ± SE ) for TMY, 305 DMY and LP were 0.11± 0.03, 0.04:: 0.02 and 0.07± 0.02, respectively.
8-Each of genetic and phenotypic correlations between traits the present under study were positive and highly Significant.
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