Evaluating differences between formulated dietary net energy values and net energy values determined from growth performance in finishing beef steers.

Feedlot growth performance and carcass data can be used to estimate dietary net energy values. The degree to which growth performance-predicted values agree with tabular energy values for feeds is an indication of how accurately the California Net Energy System can be used to predict cattle growth performance. Using data from 747 pens of cattle in feedlot research studies, we found that growth performance-predicted and tabular net energy values agreed on average, but the precision of growth performance-predicted estimates was less than desired for practical application. Based on analysis of residuals, differences in gain:feed ratio were strongly related to growth performance-predicted net energy values. Research is needed on approaches to improve the precision of growth performance-predicted net energy values.