Relationships Between DMI Fluctuation and Feeding Behavior at the Beginning and End of the Finishing Phase in Feedlot Cattle

The objectives of this study were to: 1) determine the relationships between daily individual DMI fluctuation and feeding behavior at the beginning and end of the finishing phase; and 2) determine the ability of feeding behavior traits and DMI fluctuation during the initial 28 d to predict overall growth performance. Over 2 yr, calf-fed, crossbred Angus steers (n = 222) were fed on similar finishing diets within year. Individual DMI and feeding behavior traits were recorded using the GrowSafe (Airdrie, AB) system. At the beginning and end of the finishing phase, 28 d were selected for characterization of DMI fluctuation and 10 feeding behavior traits. Daily fluctuation in DMI was calculated for each steer as the percent of days where DMI variation exceeded 30% from the DMI of the previous day. Non-feeding interval frequency (NFIF) at the beginning and end of the finishing phase was correlated (r = 0.50; P < 0.001). Bunk visit duration (BVDUR) and meal size at the beginning and end of the finishing phase was also repeatable (r = 0.80; P < 0.001, and r = 0.35; P <0.001, respectively). Variation in meal intake and head-down duration expressed as the SD of each at the beginning and end of the finishing phase was correlated (r = 0.36; P < 0.001, and r = 0.38; P <0.001, respectively). Meal size variation was not associated with fluctuation in DMI during the beginning of the finishing phase (P = 0.60) suggesting they are independent measures of feeding behavior. Meal size and variation in head-down duration were the most strongly correlated (r = 0.26; P < 0.001, and r = 0.28; P < 0.001, respectively) traits with ADG over the entire finishing phase. During the early finishing phase, BVDUR was the most correlated trait with G:F (r = 0.25; P < 0.001). Stepwise regression selected 4 feeding behaviors traits (meal size SD, DMI fluctuation, head-down duration SD, and NFIF; P < 0.05) in the beginning of the finishing phase that were able to predict 19% of the variation in ADG during the entire finishing phase. Overall, data suggest some feeding behaviors are highly repeatable during the finishing phase and may increase their utility for making management decisions or in cattle selection.