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Received: Revised: Accepted: 2013–11–26 2013–12–23 2013–12–23 The performance records of 587 Sahiwal and crossbred cattle daughters of 47 sires maintained during 1970 –o 2001 at Instructional Dairy farm, G.B. Pant University of Agriculture & Technology, Pantnagar, were used to evaluate sires for first lactation and life time performance traits. First lactation traits included were age at first calving, first lactation milk yield, first lactation period, first dry period, first calving interval, and first service period. Life time traits were herd life, productive life, lifetime milk yield, total lactation length and life time milk yield /day of productive life. The Least Squares method was used to obtain the estimates of breeding values. The estimated breeding values (EBVs) of sires showed large genetic variation between sires for both first lactation and life time traits. The product moment correlations among the EBVs of sires for first lactation traits were ranged from very low to moderate. The first lactation traits also showed same trend with life time performance traits. While product moment correlations among estimated breeding values of sires for life time traits were medium to very high. The rank correlation between the EBVs of sires for first lactation traits ranged from –025 to 0.60. The range of rank correlation among EBVs for life time traits was found to be –0.17 to 0.88. The rank correlations between EBVs of sires for first lactation traits with life time performance traits ranged from –0.28 to 0.38 respectively. Rank correlation among EBVs of sire’s indicated that all sire’s would not rank same for first lactation and life time performance traits. However, the ranks of sire’s for different traits revealed that 4–5 % top sire’s had similar rank for first lactation and life time performance traits. These results suggested that to improve lifetime productivity major culling of bulls should be done on the basis of their daughter’s first lactation milk yield. All copyrights reserved to Nexus® academic publishers

Sire Evaluation Considering First Lactation Yield for Improvement of Life Time Production in Sahiwal and Crossbred Cattle