311 - Effects of Interactive Activity at the Feedbunk on Performance, Feed Efficiency and Feeding Patterns in Feedlot Cattle

The objective of this study was to determine if the magnitude of interactive feeding activity at the feedbunk affects feed efficiency and feeding behavior patterns in beef cattle. This study used data from 498 crossbred steers (3 trials) fed high-concentrate diets in pens with electronic feed bunks (GrowSafe Systems). Timestamp data for bunk visit (BV) events were used to develop an algorithm to quantify those BV events deemed to be replacement events; Defined as those that occur when an animal displaces and replaces another animal from the feedbunk within a specified period of time (replacement criterion). For this study, a replacement criterion of ≤ 18 s was used. A replacement activity index (RAI) was computed for each steer as the number of replacement events divided by total BV events. Within pen, steers were classified into 1 of 3 phenotypes based on ± 0.5 SD from mean RAI. Steers with high RAI ( > 0.5 SD from mean RAI) were hypothesized to be more interactive at the feedbunk, whereas steers with low RAI were less interactive at the feedbunk. A mixed model with RAI class as fixed effect, and trial and pen within trial as random effects was used for data analysis. The low RAI steers had 6% fewer BV events that were 12% longer (P < 0.001) in duration than high RAI steers. Additionally, eating rate (g/min) was 14% slower (P < 0.001) and time to approach the feedbunk following feed delivery 6 min longer (P < 0.001) in low vs high RAI steers. The low-RAI steers had substantially less (P < 0.01) feeding activity during peak feeding time than high RAI. Further research is warranted to evaluate interactive feeding activity at the feedbunk as a potential indicator of performance and feed efficiency in feedlot cattle.