162 Effects of bedding application on feedlot receiving phase growth performance and estimated maintenance requirement in newly weaned beef steers

The effect of bedding application on growth performance and estimated maintenance energy requirements during the feedlot receiving phase was evaluated in newly weaned beef steers (n = 162 Charolais-Red Angus cross steers; initial un-shrunk body weight [BW] = 278 ± 13.4 kg). Steers were housed in 18 concrete surface pens (n = 9 steers/pen) measuring 7.62 × 7.62 m at the Ruminant Nutrition Center in Brookings, SD. A corn silage based receiving diet was fed that contained approximately 1.74 Mcal/kg of NEm, approximately 1.12 Mcal/kg of NEg, and monensin sodium at 27.6 g/T. Pens were assigned to one of two treatments: 1) no bedding (NO), or 2) 1.0 kg (as-is basis) of wheat straw bedding/steer/d (BED). The study was conducted from October to December of 2019. Daily ambient temperature (n = 56) averaged -3.0°C [SD 5.5] and windchill averaged -5.1°C [SD 6.1] during the course of the study. Data were analyzed using the GLIMMIX procedure of SAS 9.4 (SAS Inst. Inc., Cary, NC) as a randomized complete block design with pen serving as the experimental unit. An α of 0.05 determined significance and tendencies were declared from 0.06 to 0.10. At study initiation, initial un-shrunk body weight did not differ (P = 0.69) between treatments. Bedding application did not influence (P ≥ 0.66) final body weight (shrunk 4%) or average daily gain. Dry matter intake tended to increase (P = 0.06) by 3.8% in NO compared to BED. Gain to feed was increased (P = 0.01) by 5.6% in BED compared to NO. Maintenance coefficient (MQ) was elevated (P = 0.03) 18.9% for NO compared to BED. These data indicate that bedding application improved feed efficiency and reduced estimated MQ in beef steers during the feedlot receiving phase.