Influence of Close-Up Starting Programs on Performance of Light-Weight Feedlot Steers Calves during the Early Receiving Period

The influence of close-up feed strategies on growth performance and dietary NE in light-weight feedlot steers during a 56 d receiving period was evaluated. Dietary treatments were formulated to meet the average metabolizable amino acid requirements of calves during 1) the initial 7 d; 2) the initial 14 d; and 3) the initial 21 d following arrival into the feedlot, assuming average interval DMI of 2.8, 3.0, and 3.6 kg/d, respectively. Thereafter, all steers received dietary treatment 3. Fish meal was the source of supplemental protein. One hundred eight medium-framed crossbred steers (168.4 ± 5.0 kg) were blocked by weight and assigned to 18 pen groups (6 steers per pen). P-value (≤0.10) was considered as statistically significant. Daily weight gain (linear effect, P = 0.09) and gain efficiency (linear effect, P = 0.08) decreased as the close-up interval increased. DMI was not influenced by feeding program (P = 0.46). The ratio of observed to expected dietary NEm (linear effect P = 0.06) and NEg (linear effect, P = 0.05) decreased as length of close-up interval increased. Morbidity was low (18%) and not affected (P > 0.40) by dietary treatments. It is concluded that the addition of a close-up diet formulated to meet the metabolizable amino acid requirements of shipping stressed calves during the initial 7 d in the feedlot, when feed intakes are comparatively low, will have long-term beneficial effect on cattle growth performance and dietary NE.