GENETIC EVALUATION OF MILK YIELD IN HOLSTEIN- FRIESIAN RAISED IN EGYPT USING SINGLE- AND MUL TI- TRAIT ANIMAL MODELS | ||||
| Journal of Animal and Poultry Production | ||||
| Article 4, Volume 28, Issue 2, February 2003, Page 873-884 PDF (7.35 MB) | ||||
| Document Type: Original Article | ||||
| DOI: 10.21608/jappmu.2003.243308 | ||||
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| Authors | ||||
| S. M. Zahed,1; M. A. Salem1; M. H. Khalil2; Samira A. Arafa1 | ||||
| 1Animal Production Research Institute, Ministry of Agriculture, Dokki, Cairo, Egypt. | ||||
| 2Department of Animal Production & Breeding, College of Agriculture and Veterinary Medicine, King Saud University, Saudi Arabia. | ||||
| Abstract | ||||
| Single-trait (SAM) and multi-trait (MAM) animal model were compared using the dal\) of 9().day (M90) and 305-days- (M305) milk yield of 985 of Holstein-Friesian cows daughters of 104 sires and 985 dams in Egypt. Data included 985 first lactation records. Total number was 5M2 for all lactations. Animal model in both single- and multi· trait. contailled season. year of calving. classes of age at calving and days open as frxed effects and animal and residual as random effects. The variablity in predicted breeding value, PBV (i.e., range from maximum - mfnmum) was large for MAM in first lactation. however, the reverse trend was found in all lactations (i.e .• ranges of PBV in SAM was larger than the estimates from MAM). Using MAM decreased the standard error of prediction (SEP) and consequently the accuracy (rn) increased . Closeness between rpM and rs of both SAM and MAM prove thai any model may be effective in the evaluation of sires. dams and cows. Using records of all lactation reduced SEP in both SAM and MAM procedures than those of first lactation only. Inerasing accuracy with all lactations was maltedly pronounced when compared with the first lactation. Increasing information from all lactations has a direct effect toward increasing the accuracy (rTI) of the all lactaion than using only first ladation. Oisclosness between correlations (rPM & rs) of PBV and ranks in first and alliactalions, indicate that the sires, dams and cows were reran ked when using firsllactation and all lactation records. Part-lactation yields (MOO) in both first and alilactalion records proved 10 be a good parameter in estimating sire genetic values without complications and would also afford an opportunity for a faster return for sires. Reduction in sires, dams and COWS SEP by using MOO compared with M305 using either SAM or MAM provided a considerable potenti;lll for rapid genetic progress through sire selection, (l.e. there is a considerable polientlal for improving milk production through selection of bull or bull· dam's of Holstein population). | ||||
| Keywords | ||||
| Holstein cattle; milk yield. breeding values; animal models; accuracy | ||||
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