COMPARATIVE FEEDING VALUE OF HULLESS VS COVERED BARLEY FOR FEEDLOT CATTLE

One hundred twenty medium-frame crossbred steers (364 kg) were used in 106-d feedlot trial to compare the feeding value of Condor, a hulless barley (HB), with Leduc, a conventional covered barley (CB). Dietary treatments consisted of a finishing diet containing 77% grain (DM basi s) as 1) steam-flaked corn (SFC); 2) dry-rolled HE (DRB-H); 3) steam-f laked HB (SFB-H); 4) dry-rolled CB (DRB-C); and 5) steam-flaked CB (SF B-C). Feed intake was lower (8.6%, P < .01) for HB than for CB. Diet N E was greater for HB than for CB (P < .01) and for SFB than for DRB (P < .01). Incidence of liver abscess was greater for DRB than for SFB ( 239%, P < .05) and for HB than for CB (167%, P < .10). Diet NE were gr eater(P < .10) for SFC than for barley treatments. Treatment effects o n characteristics of digestion were evaluated using five Holstein stee rs (202 kg) with cannulas in the rumen and proximal duodenum. There we re barley variety x grain processing interactions on ruminal digestion of OM (P < .10), ADF (P < .05), and starch (P < .05). Ruminal OM dige stion increased (9.0%) with steam flaking HB and decreased slightly (1 .9%) with steam flaking CB. Ruminal digestion of starch was enhanced m ore dramatically (21.5 vs 8.4%, respectively) with steam flaking HB th an with CB. Steam flaking decreased ruminal ADF digestion of HB only s lightly (6.2%), whereas with CB the decrease was more dramatic (54.3%) . Ruminal degradable N was greater (P < .10) for CB than for HB and fo r DRB than for SFB (19.8%, P < .05). Estimates of ruminal degradable N in DRB-H, SFB-H, DRB-C, and SFB-C were 69.7, 53.9, 78.5, and 65.0%, r espectively. Postruminal digestion of OM (P < .01), starch (P < .05), and N (P < .10) were greater for HB than for CB. Steam flaking barley increased(P < .01) postruminal N digestibility. Total tract digestibil ity of OM (P < .01), ADF (P < .05), starch (P < .01), and energy (P < .01) were greater for HB than for CB. Digestibility of ADF in barley h ulls was only 6.4%. Steam flaking increased (P < .01) total tract dige stibility of starch. Ruminal digestibility of OM and feed N was lower (P < .01) for SFC than for barley diets. Ruminal pH was lower (P < .10 ) for HB than for CB and for SFB than for DRB (P < .01). Ruminal propi onate was higher (24.1%, P < .01), and methane was lower (17.9%, P < . 01) for HB than for CB.