Fifty-four Holstein steer calves, divided in two weight groupings (141.2 ± 4.9 kg and 454.2 ± 7.0 kg respectively), were used in a 56-day study to evaluate the influence of supplemental vitamin E on growth performance and plasma vitamin concentrations. Steers were assigned within body weight groupings to 18 pens, 3 steers/pen. Dietary treatments consisted of a steam-flaked corn-based growing-finishing diet supplemented to provide 0, 250, or 500 IU/d of vitamin E as all racemic αtocopherol. No morbidity was apparent during the course of the study. Calves in the heavier weight grouping had greater average daily gain (24.4%, P < .01), dry matter intake (54.3%, P < .01), and lower gain efficiency (40.7%, P < .01). Vitamin E supplementation did not affect (P > .10) feedlot growth performance. Initial and 56-day plasma tocopherol were not influenced (P > .10) by weight grouping. Final 56-day plasma tocopherol increased linearly (P < .01) with level of vitamin E supplementation. Plasma tocopherol of non-supplemented steers decreased (P = .01) from an average initial concentration of 1.66-1.16 ug/mL at day 56. It is concluded that vitamin E supplementation of calf-fed Holstein steers receiving a conventional steam-flaked corn-based growing-finishing diet is not expected to enhance growth performance.

One hundred twenty-six Holstein steers (457.1 ± 27.5 kg BW) were used in a 127-d experiment to evaluate the influence of dietary cation-anion difference (DCAD) on growth performance and carcass characteristics. Treatments consisted of steam-flaked corn-based diets supplemented to provide DCAD of 34, 84 or 134 mEq/kg diet DM. There was no treatment effect (P > .20) on ADG, DMI, gain efficiency or dietary NE. Six Holstein steers (196 ± 3 kg) with cannulas in rumen and proximal duodenum were used in a replicated 3 × 3 Latin Square design to evaluated treatment effects on digestion characteristics. The DCAD did not affect (P > .20) ruminal or total digestion of OM, NDF, starch and N, or ruminal pH and VFA molar proportions. It is concluded that increasing DCAD of Holstein steers fed a conventional steam-flaked corn-based diet under conditions of high ambient temperature will not enhance growth performance. ARTICLE HISTORY