Effect of Time of Supplementation on Performance and Grazing Behavior of Grazing Steers

Beef cattle follow a daily, cyclical pattern of grazing, rumination, and digestion that coincides with their environment and season. Traditionally backgrounding operations hand feed any supplement in the morning. However, this practice may interrupt typical grazing patterns during early morning and subsequent rumination during the heat of the day. Self-fed concentrate feeds containing intake limiters are used to minimize the labor associated with hand feeding and allow cattle to eat throughout the day. The objectives of this experiment were to investigate the effect of supplement feeding time on performance and grazing behavior of backgrounded beef steers. Crossbred beef steers (n = 54; 7 ± 1 m of age; body weight, BW = 243 ± 2 kg) were sourced from a regional cattleman's association and grazed on tall fescue pasture (Festuca arundinacea) at the Southwest Virginia Agricultural Research and Extension Center in Glade Spring, VA from October 1 to November 7, 2019. Cattle were stratified by BW and source and allotted to 9 pasture groups (6 steers per pasture) in a randomized design. Pasture groups were randomly assigned to 1 of 3 treatments (3 pastures per treatment): 1) steers hand-fed supplement at 0930 h (AM), 2) steers hand-fed supplement at 1330 h (PM), or 3) steers fed a self-feeder supplement with an intake limiter (SELF). Hand-fed groups were fed a commercial commodity blend (38% corn gluten feed pellets, 30% cracked corn, 22% soy hull pellets, and 10% dried distillers grains) daily at 1.5% BW on an as fed basis. The SELF supplement was a blend of 70% cracked corn and 30% of an intake limiter-containing pellet that was formulated to maintain voluntary supplement intake at 1.5% BW on an as fed basis. Cattle were weighed on 2 consecutive days at the start and end of the experiment, and feed adjustments were made following three interim weigh-ins. Motion-sensing cameras were used to monitor cattle visits to the feeder and waterer portions of the pasture. Treatment did not impact (P = 0.13) BW, flesh condition score (FCS), dry matter intake (DMI), average daily gain (ADG), and backfat thickness. SELF steers were significantly more feed efficient than the AM supplemented groups (P = 0.03) and tended to be a greater G:F ratio (P = 0.08) for the PM supplemented groups vs. AM supplemented steers. Steers with access to a self-feeder showed behavioral differences to hand supplemented cattle, with more feeder visits in a 24 h period (P = 0.01) compared to AM and PM steers. Despite these behavioral observations, any disruption in natural grazing behavior was not dramatic enough to negatively influence backgrounded cattle growth performance.