Pakistan Journal of Biological Sciences1028-88801812-5735Asian Network for Scientific Information10.3923/pjbs.2006.723.728OudahE.Z.M. H.G. El-Awady 4200694Records of Birth Weight (BWT) and Weaning Weight (WWT) of 1184 Friesian cattle calves (591 male and 593 female), progeny of 49 sires during the period from 1990 to 2000 were analyzed. The objective of this study was to construct selection indexes for selecting Friesian calves on the basis of pre-weaning growth traits included birth weight, weaning weight and Average Daily Gain (ADG) from birth to weaning. The data were analyzed using Least Square Maximum Likelihood Computer Program. Heritability estimates (±SE) were 0.24±0.08, 0.28±0.08 and 0.28±0.08, for BWT, WWT and ADG, respectively. The genetic and phenotypic correlations between WWT and ADG were high and positive (0.907 and 0.892, respectively), while the corresponding correlations between BWT and ADG were low and negative (-0.285 and -0.278, respectively). Four selection indexes were constructed. Index 1 = -1.029 BWT+1.459 WWT -1.207 ADG, index 2 = 0.2201 BWT+0.2077 WWT, index 3 = 0.2426 BWT+0.0991 ADG and the index 4 = 0.1525 WWT+0.0960 ADG. The correlation between the index and the aggregate genotype varied between 0.50 and 0.52. Index 1 which incorporate all traits was the best (RIH = 0.52) and through this index could be improve all traits together. The present results indicated that genetic improvement for pre-weaning growth traits of Friesian calves could be achieved through multiple trait selection indexes.]]>Abdel-Glil, M.F. and M.K. El-Banna,2001269999Abdel-Moez, K.A.,19961996Afifi, Y.A. and A.M. Soliman,19714911Alim, K.A. and A. Taher,19794911721172Amir, P.R., R. Crump and G. Simm,199867445445Badawy, L., M.S. Kassab and A.S. Khattab,200228252259Badran, A.E. and A.S.A. El-Barbary,1986314150Bennett, G.L. and K.E. Gregory,19967425982611Cunningham, E.P.,1975465561Dzama, K., J.P. Walter, F. Ruvuna, J.O. Sanders and M. Chimonyo,2001316565El-Awady, H.G.,20032833933393El-Awady, H.G.,200430559559El-Gaffarawy, A.A.,19791979Emam, A.M.,20002000Harvey, W.R.,1990Hazel, L.N.,194328476476Henderson, C.R.,19539226252Kabuga, J.D. and K. Agyemang,1984224545Koots, K.R., J.P. Gibson and J.W. Wilton,199462825825Khalifa, H.A.A. and M. Khalafallah,197996203203Lee, C., C.P. Van Tassell and E.J. Pollak,199775325330Lengyel, Z., I. Komlosi, V.T. Lenyelne, T. Major and F. Szabo,20022002Maarof, N.N., S.A. Magid and A.M.S. Al-Ani,198873540MacNeil, M.D., J.J. Urick and W.M. Snelling,198876458467M.A.L.R.,20002000Oudah, E.Z.M.,20022002Oudah, E.Z.M. and A.F.A Mehrez,20002000pp: 689689Peterson, T.R and M.B. Willis,19742nd Edn.,Sadek, R.R.,20022002pp: 141141Smith, G.M., D.B. Laster and K.E. Gregory,1976432727Tabler, K.A. and R.W. Touchberry,19553811551163Tabler, K.A. and R.W. Touchberry,195942123126Vandepitte, W.M. and L.N. Hazel,197798787