Effect of Age of Dam and Sex on 205-D Weight of Senepol Calves1

Abstract Data (3,710 observations) were collected from two farms by the Virgin Islands Agricultural Experiment Station from 1978 to 1987. Data were analyzed to determine the adequacy of standard Beef Improvement Federation (BIF) age of dam (AOD) and calf sex (SEX) adjustment factors for 205-d weaning weight (WWT) for use on Senepol cattle. The mixed model contained the random effect of contemporary group (CG) and the fixed effects of SEX (bull and heifer), AOD (2 to 11+ yr), and SEX by AOD interaction. In the least squares analysis, CG, SEX, and AOD were highly significant for WWT. The interaction of SEX by AOD was not significant. Estimates of AOD adjustment factors indicate that 2-, 3-, 4- and 11 +-yr-old dams are being overadjusted using BIF correction factors. Adjustments developed by this analysis more adequately fit the Senepol data.