Feed efficiency in cow-calf operations can be influenced by multiple environmental and physiological factors. The current study examined the association between body size (weight, frame score, and volume), linear body measurements, and feeding behavior with different measures of feed efficiency in multiparous lactating beef cows. Prediction models for dry matter intake in cows using linear body measurements were also developed. Our findings indicate that body size measurements and feeding behavior may influence measures of efficiency. The inclusion of body measurements in prediction models of intake may serve as accurate and feasible methods for estimating intake of cows on farm. The associations between the traits measured may provide insight for further producing models to measure and predict efficiency traits that are easily accessible on farm. Body measurements and feeding behavior are two traits that should be accounted for when considering efficiency and selection criteria for cow-calf operations.