An Assessment of the ARC Metabolizable Energy System to Predict Live Weight Gain of Brown Swiss Cattle Grown under Feedlot Conditions in Turkey

A set of data from Brown Swiss cattle grown under feedlot conditions was used to evaluate the energy feeding system adopted by the Agricultural Research Council (ARC) in the United Kingdom in order for prediction accuracy of beef performance. The discrepancies between observed and predicted values of Live weight Gains (LWG) were small (0.012 0.057) and there was a substantial agreement between observed and predicted values by the model in the test data. There was no significant difference between the discrepancies. LWG predictions by the model were 0.98 times (or 11.6%) less for the test data. The high regression and correlation coefficients (0.93 and 0.97, respectively) and the very low mean prediction error MPE (0.00122) indicate model prediction ability. The Mean-square Prediction Error (MSPE) was used for the evaluation of the equations used for the model. Live weight gains were underpredicted especially for the observed values less than 0.9 kg/day. The MSPE of the predictions by the model was 0.0013 kg/day for this data set. In terms of contribution of components to MSPE; the values of bias, line and random error were 11, 0.1 and 88.9%, respectively. The model had a greater proportion of error derived from random than other components. A small proportion of line as a component of MSPE showed that the error derived from line was substantially low and there was a minimal variation between predicted and observed LWGs. The accuracy of measurement and error of experimentation and predictions were within the acceptable range for the observed values for the data examined in this study. Although the model based on the energy system may have limitations due to the empirically derived equations, the data presented in this study indicated that the model provides very close agreement with reality for prediction of live-weight gain.