On January 16, 2018, the feature article in Beef and Beef Producer magazines was about Lukefahr Ranch (http://www.beefproducer.com/management/another-study-says-smaller-cows-more-profitable). Actually it was one of a two-part series. This part I article describes a model simulation on cow and land efficiency. My simulation dealt with figures on cow size (1100, 1200, 1300, and 1400 lbs) and total annual costs per cow ($300, $600 or $900) – ultimately relating to the bottom line in terms of profit per acre. After sending this information to Alan Newport last summer, he requested my permission to summarize this information into an article for these magazines. The part II article will describe breeding management practices on Lukefahr Ranch.