Over the past years, several measures of feed efficiency have been used (Archer et al., 1999) to identify superior animals, feeding strategies, and genetics. Most studies to date have put emphasis on evaluating feed efficiency in young growing cattle, particularly in the feedlot sector. However, emphasis in replacement heifers, developing bulls, and mature cows is growing. For years, a measure of efficiency in an animal was determined using gross feed efficiency or a feed conversion ratio. Gross feed efficiency is the ratio of live-weight gain to DMI where the higher the value the more desirable. Feed conversion ratio (FCR) is the ratio of DMI to gain where the lower the value the more desirable. Feed conversion ratio is the most widely used method of determining feed efficiency and is typically measured as a group compared to an individual animal. Reason being, intake must be determined and most facilities/feedlots are not equipped to measure individual DMI on a daily basis. One of the downfalls of feed conversion ratio is that it does not account for maintenance requirements of an animal (Archer et al., 1999) and is negatively correlated with post weaning ADG, yearling BW, and mature cow size (Herd and Bishop,