COMPARISON BETWEEN SIRE AND ANIMAL MODEL TO ESTIMATE GENETIC (CO)VARIANCES FOR MILK YIELD TRAITS | ||||
| Journal of Animal and Poultry Production | ||||
| Article 3, Volume 1, Issue 11, November 2010, Page 603-612 PDF (543.37 K) | ||||
| Document Type: Original Article | ||||
| DOI: 10.21608/jappmu.2010.86273 | ||||
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| Authors | ||||
| H G El-Awady1; Zainab A. Khalifa2; A. S. Khattab3; E. Z. M Oudah4 | ||||
| 1Animal Production Dept., Fac. of Agriculture, Kafrelsheikh University, PC: 33516, Kafrelsheikh, Egypt, | ||||
| 2Animal Production Res. Inst., Ministry of Agric., Dokki, Giza, Egypt | ||||
| 3Animal Production Department, Faculty of Agriculture, Tanta university Egypt | ||||
| 4Department of Animal Production, Faculty of Agriculture, Mansoura University, PC: 35516, Al Mansoura, Egypt. | ||||
| Abstract | ||||
| Records of 847 Friesian cows which completed one or more lactations of milk production kept at Sakha and El–Karda farms during the period from 1996 to 2002 were used to estimate the genetic and phenotypic (co)variances of and between three months and 305 day milk yield traits by using sire and animal model. Sire model, included the fixed effects of HYS and parity, Days open was used as a covariate, while the random effects were sire, cow and dam and residual effect. Animal model included the same effects in the sire model and increase the animal direct genetic effect and permanent environmental effect as the random effects. The average number of mixed model equations (MME), no. of iterations, CPU for solving and inverting and AG-Log Likelihood were higher for multi trait than single trait for both sire and animal model. Estimates of heritability (h2) of milk traits, for sire model were moderate, ranged from 0.096 to 0.276 for single trait and from 0.116 to 0.264 for multiple traits. While the h2 for milk traits from animal models ranged from 0.001 to 0.031 for single trait and from 0.046 to 0.062 for multiple traits. Heritability estimates for milk traits in single and multiple traits from both sire and animal model were nearly similar. Genetic correlations between yield traits were positive, high and near similar for both sire and animal model and ranged from 0.88 to 0.99. The high estimates of genetic correlation in the present study offer the possibility to select for yield traits as early ages, .i.e., at 90 days of lactation. Also, this study indicate that, using of sire model is useful when, small number of observation and little pedigree information | ||||
| Keywords | ||||
| Friesian cattle; genetic parameters; variance component estimation; milk traits | ||||
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