435 - Effect of Time of Supplementation and Supplement Delivery Method on Performance and Grazing Behavior of Backgrounded Beef Steers

Objectives were to investigate effects of supplement feeding time and delivery method on performance and grazing behavior of backgrounded steers. Crossbred steers (n = 109; 7 ± 1 m of age; BW = 245 ± 2.9 kg) were stratified by BW and source into 18 groups (6-7 steers per group), and randomly allotted to tall fescue pastures during 38 and 45-d treatment periods during fall of 2019 and 2020, respectively. Pasture groups were randomly assigned to 1 of 3 treatments (6 pastures per treatment): 1) steers hand-fed a commodity blend supplement at 0930 h (AM), 2) steers hand-fed supplement at 1330 h (PM), or 3) steers fed a commercially available self-fed supplement with an intake limiter (SELF). All treatments were formulated for as fed supplement intake of 1.5% BW. Pedometers were used to estimate animal activity level. Motion-sensing cameras were used in yr 1 to monitor feeder and waterer visits. Data were analyzed using the MIXED procedure in SAS with main effects of year, group, and treatment with pasture as a random effect. Treatment had no effect (P ≥ 0.13) on calf BW, flesh condition score, ADG, or ultrasound 12^th rib fat thickness. Supplement DMI tended (P = 0.08) to be greater for SELF relative to hand-fed cattle, with yr 2 tending (P = 0.07) to be greater than yr 1. There was a treatment x year interaction (P = 0.04) for G:F with SELF and AM steers in yr 1 tending (P ≤ 0.09) to be greater than SELF in yr 2, with all other treatments being intermediate and not different. Self-fed cattle had greater (P ≤ 0.01) activity level and more (P = 0.01) visits to feeders relative to hand-fed treatments. Results indicate that performance of backgrounding steers was not greatly impacted by supplementation schedule or delivery method.