Can. J. Anim. Sci. 63:715-719 (Sept. 1983) diet reduced the incidence of bloat in the first of these two trials. Brethour (1912) also found variable results with the addition of I g thiamin and 100 g sodium bicarbonate to a wheat-based ration for steers.It is not known whether subclinical deficiencies, which could limit animal production and possibly cause health problems in f'eedlot cattle, occur to any significant extent. T'he purpose of this survey was to determine, using the TPP effect (Brin 1970) 'day t of the diet (Table I ) and increasing the ration by 0.5 kg'head-''day 'until full feed was achieved (10-14 days). These data were treated as a single source of information and thus the diet reported for this location reflects the range of feed ingredients used (Table l).Samples were also collected at a commercial feedlot in Brooks, Alberta from 100 steers (average initial weight 269 kg) 6 days following the achievement of full feed (Table l). These animals were initiated onto feed by gradually increasing the concentrate portion of an 85% silage diet over a period of 3 mo (Table 1).Nutrients in the feeds were determined using procedures outlined in the Association of Official Agricultural Chemists ( r e80).In addition to data obtained from these sources, results from previously published works Mathison 1982, 1983) have been included to allow for comparison of these data with those of the oresent For personal use only.