This analysis of nearly 15,000 head of fall placed calf-feds found similar results to 2002 ISU work in spite of 22% higher corn prices and 38 % higher cattle prices. The data does show strong correlations between economically important carcass and production variables, some of which are antagonistic. Carcass weight has a strong positive correlation with REA and ADG; that is faster growing cattle have larger carcasses with larger ribeyes. As MS increases so does FC and FG; thus higher marbling cattle put on more external fat and require more feed per pound of gain. Also, as ADG increases FG decreases, a favorable outcome. Marbling is less correlated than some variables, but has a positive relationship with ADG, but negative with REA, PW and HT.

In general, the relative importance of each variable in the model on net return in the feedlot was less pronounced in this analysis than in previous work. The difference may be explained by the inclusion of placement weight and individual health treatments that were not in the earlier study. There are also almost thirteen times more observations in this analysis that may have moderated the impact of any one variable. In both studies marbling was identified as having the largest relative impact on net returns for feedlot cattle when the Choice-Select spread is $8/cwt or higher. The Choice-Select spread where the relative importance of marbling score is equal to other factors is approximately $6/cwt in the current analysis. The relative importance ranking of carcass and management variable was similar in this analysis to previous work. Hot carcass weight and feed to gain were next behind marbling followed by ribeye area. Placement weight is strongly correlated to carcass weight and statistically may be capturing part of the variation that was explained by carcass weigh in the earlier model.