An evaluation of the ME system model to predict performance of different breeds of feedlot beef cattle fed under two different feeding periods

In this study, data from Holstein, Brown Swiss, Simmental cattle as European Type (ET) and Boz and Gak as Indigenous Type (IT) grown under feedlot conditions were used to evaluate the ARC, ME system for prediction of beef performance during two different feeding periods. During growing period, the discrepancies between observed and predicted values of daily liveweight gains (OLWG and PLWG) were high and significant (p<0.05) for all cattle. OLWGs were underpredicted for IT cattle and those observed values less than 0.9 kg days(-1). The Mean-Square Prediction Error (MSPE) of the predictions by the model was 0.03 and 0.007 kg day(-1) for ET and IT, respectively. During finishing period, the discrepancies between OLWGs and PLWGs were low and were not significant (p>0.05) for all cattle except Gak and there were substantial agreement between observed and predicted values for ET. The model tended to underpredict OLWGs of ET while OLWGs were overpredicted for IT and those OLWGs less than 0.6 kg day(-1). The MSPE was 0.006 and 0.02 kg day(-1) for ET and IT, respectively. The accuracy of measurement predictions were within the acceptable range only for OLWGs obtained for ET at finishing period. The results indicated that the model does not provide very close agreement with reality for prediction of LWG for IT cattle.