The study was conducted at Holeta Bull Dam Station and Genesis Farms with the objective of evaluating age at first effective service (AFS), age at first calving (AFC), days open (DO), number of service per conception (NSC), calving interval (CI), lactation milk yield (LMY) and lactation length (LL). Data recorded in the Holeta Bull Dam Station from 1997 to 2003 and in Genesis Farms from1996 to 2005was used for this study. the independent variables considered included location, birth year and season, calving year and season and parity while AFS, AFC, DO, CI, NSC, LMY and LL were the dependent variables. Data were analyzed using The General Linear Models procedure (GLM) of the Statistical Analysis System (SAS 2002). The results indicated that the overall least squares means (± standard error) of AFS, AFC, DO, CI, NSC, LMY and LL were 733 ±16 days, 1001 ± 17days, 202 ± 13 days , 470 ±12days, 2 ± 1, 4097± 1491liters and 301±91days, respectively. Location had highly significant (p