PSI-9 Effect of replacing cottonseed hulls with a low-quality forage pellet on intake, digestion, and performance in growing Bos indicus steers.

Abstract Decreases in roughage supply and resultant increase in price has caused many beef producers to seek roughage alternatives, including lower-quality forages. One strategy to increase the utility of lower-quality forages is pelleting. Two experiments were conducted to evaluate the effect of replacing cottonseed hulls with a forage pellet on performance, digestibility, and ruminal fermentation in growing steers. In Exp. 1, 18 Brahman steers (initial BW = 246 ± 32 kg) were sorted according to initial BW and assigned to 1 of 7 pens. Within pen, steers were randomly assigned 1 of 2 dietary treatments: 1) 10% cottonseed hull (C10) and 2) 10% forage pellet (FP10). Steers were fed at 2.25% of BW as-fed split into two daily feedings. Steers were fed for 84 days, and bodyweight was recorded every 28. On d 85, all steers were transitioned to C10 for 4 days to account for differences in fill and reweighed on d 89. In Exp. 2, 5 ruminally cannulated Brahman steers (initial BW = 247 ± 13 kg) were used in a 2-treatment crossover design to quantify intake, digestion, and ruminal fermentation responses to a growing ration with a pelleted forage source. Dietary treatments were replicated from Exp. 1. Two 21-d periods were conducted with 15 days to adapt steers to treatments and 6 days to determine intake, digestion, and ruminal fermentation. In Exp. 1, no treatment effects (P > 0.10) were observed for final steer weight (331.5 kg), ADG (1.02 kg/d), as-fed intake (6.07 kg/d) and feed efficiency (0.170 kg gain/kg feed). In Exp. 2, there was no significant treatment effect on DM intake (4.77 kg/d; P = 0.87). However, OM intake was greater (P = 0.03) for C10 (4.40 kg/d) than FP10 (4.29 kg/d). In contrast, starch intake was greater (P = 0.05) in FP10 (0.50 kg/d) versus C10 (0.41 kg/d). There were no significant treatment effects (P ≥ 0.16) for digestion of DM, OM, NDF, and ADF. A tendency (P = 0.07) was observed for greater starch digestion in FP10 compared to C10 steers (99.6% and 98.4%, respectively). Accordingly, digestible starch intake was greater (P = 0.05) in FP10 than C10 (0.49 versus 0.41 kg/d, respectively). No treatment effects were observed for VFA concentration (P = 0.12), but a tendency was observed for pH to be lower (P = 0.09) with FP10 (6.10) than C10 (6.26) and for NH3 concentration to be greater (P = 0.06) for FP10 (8.40 mM) than C10 (5.17 mM). Similar performance, digestibility, and fermentation results with either cottonseed hulls or a forage pellet suggest that at equalized intakes, utilizing a pelleted, lower-quality forage source may be a suitable replacement for some commonly used roughages.