Impact of high-energy forages on grass-finished steer performance and carcass merit

Abstract Text: The research objective was to compare high-energy forage options during the finishing period for Upper Midwestern forage-finished beef production systems. Twelve 0.80-ha pastures were randomly assigned to 1 of 3 forage treatments including: mixed pasture (MIX); simple cereal grain/brassica mixture (SIMP); and complex cereal grain/brassica mixture (COMP). Red Angus-influenced steers (BW = 439.99 kg ± 4.21, n=24) were stratified by BW and randomly assigned to 1 of 12 paddocks and were grazed for a 76 d finishing period. Steers had ad libitum access to water, free choice mineral, supplemental hay, and were allowed access to strips in each grazing treatment, which were back fenced to allow for forage regrowth. Overnight fasted BW was measured on d 0, 36, 66 and 76. At the end of the finishing period, steers were slaughtered under Federal Inspection and carcass data were collected 48 hr post-mortem. Data were analyzed using Proc Mixed (SAS v 9.4) where paddock was the experimental unit. Steers had different d 0-76 BW gains (P < 0.01), where gains were greatest for MIX (90.15 kg ± 3.32), followed by COMP (73.71 kg ± 3.32) then SIMP (64.64 ± 3.32). Although overall BW gains were greatest for steers in MIX, there was a tendency (P = 0.11) for d 67-76 gains to be highest in COMP and least for MIX (19.28 kg ± 2.07 and 12.47 kg ± 2.07, respectively).There was a treatment by period interaction for d 76 BW (P < 0.01) where steers on COMP and SIMP had less BW (514 kg ± 4.7 and 505 kg ± 4.7, respectively) than MIX (530 kg ± 4.7) yet each had greater (P < 0.01) dressing percents (56.95% ± 0.44 and 59.96% ± 0.44, versus 54.67% ± 0.44, respectively).There were no differences (P > 0.05) among steer carcasses from all treatments for HCW, backfat, LM area, KPH, YG and marbling score. These data indicate steers grazing all treatments had reasonable gains and carcass merit and that these systems can be a viable component of forage-finishing systems in the Upper Midwest.

Keywords: brassicas, beef, grass-finished