Fed cattle profitability is determined by complicated dynamic processes of body growth, carcass development, and seasonal prices. A structural model is constructed to contend with all these dynamic processes to predict optimal market timing. Informed simulations are conducted and compared to those observed in the data, as well as to a previous model ignoring the evolution of carcass value. The results indicate that significant improvements to profitability are attainable with the new method. The results also indicate the opportunity cost of not accounting for carcass value, even with error, is more severe than when these dynamics are ignored.