Pakistan Journal of Biological Sciences1028-88801812-5735Asian Network for Scientific Information10.3923/pjbs.1999.211.213AliAfzal AhmadZaheer MohiuddinGhulam JavedKhalid 1199921Pedigree and performance of 878 Nili-Ravi buffaloes progeny of 38 sires maintained for 47 years were recorded at Livestock Production Institute, Bahadurnagar, Okara, Pakistan. The phenotypic correlations of age at first calving with lifetime milk yield, productive life, herd life and coefficient of reproductive ability were negative and significant. However, the phenotypic correlation (0.03) between age at first calving and longevity was non-significant. The genetic correlations of age at first calving with lifetime milk production, productive life, herd life, longevity and the coefficient of reproductive ability were -0.52, -0.41, -0.44, -0.11 and -0.60, respectively. These negative and significant genetic correlations indicated that reduction in age at first calving in buffaloes would help to improve lifetime milk yield, longevity and reproductive ability as a correlated response.]]>Anonymous,19971997Asker, A.A., L.H. Bedeir, A.A. Alitribt, I.A. Ahmad and S.S. Khishin,19699173179Becker, W.A.,19925th Edn.,pp: 113-117pp: 113-117Bhatnagar, D.S. and R.C. Sharma,19833237240Dutt, T. and V. K. Taneja,199666371374Essl, A.,198254267275, (In German)Gopal, D. and D.S. Bhatnagar,197225129133Hussain, S.M.,19881988Kalsi, J.N. and J.S. Dhillon,198235218219Larson, C.J., A.B. Chapman and L.E. Casida,19513411631169Lin, C.Y. and F.R. Allaire,197861489496Rao, A.V.N. and H.R.M. Rao,199774906907Singh, B.B. and N.S. Tomar,198158303307Bhatia, S.S.,198050450453