Abstract Processed corn is generally thought to improve digestibility and enhance cattle performance; however, depending on the processing method, processing may not always be beneficial. This study evaluated growth performance, feed intake, and carcass characteristics of finishing crossbred steers fed diets based on whole corn or dry-rolled corn with 5 or 15% forage inclusion. Seventy-three steers (initial BW ± standard deviation = 330 ± 38.5 kg) were stratified by initial BW, assigned to treatment (2 × 2 factorial arrangement of treatments in a randomized block design), and fed using an Insentec automated feeding intake monitoring system for ad libitum intake. Treatments were corn processing (whole vs. dry-rolled) and with forage included at 5 or 15% of the diet DM. Individual feed intake was recorded daily, BW was measured on two consecutive days at the beginning of the feeding period, every 28 days thereafter, and again on two consecutive days before slaughter. Forty steers were slaughtered after 175 days on feed, while the remaining steers were slaughtered after 203 days on feed. Carcasses were evaluated for hot carcass weight, dressing percentage, KPH fat, marbling score, backfat thickness, and longissimus muscle area at a commercial facility. Data were analyzed using the MIXED procedure of SAS, with corn processing (whole vs. dry-rolled), forage inclusion level (5% vs. 15%) as fixed effects. Slaughter group was included as a blocking factor in the model. Least square means were compared, and significance was declared at P ≤ 0.05 and trends were considered at 0.05 P ≤ 0.10. Gain:feed tended to be improved in steers fed dry-rolled corn compared to those fed whole corn (P = 0.07). Dry matter intake was greater in steers fed diets containing whole corn (P = 0.004) and in steers fed diets containing 15% forage (P 0.001). The number of visits to the feed bunk per day was greater in steers fed diets with 15% forage (P = 0.01), while meal size was larger for steers consuming dry-rolled corn (P = 0.007). Dressing percentage was greater (P = 0.06) in steers fed dry-rolled corn and tended to be greater (P = 0.07) in steers fed 5% forage. Overall, these results suggest that while feeding diets containing dry-rolled corn resulted in reduced feed intake and improved gain:feed, ADG and carcass characteristics were largely unaffected. Therefore, the choice to feeding whole vs. dry-rolled corn is dependent on the costs of processing relative to the improvement in gain:feed regardless of forage inclusion level (5 vs. 15%).
Finck et al. (Wed,) studied this question.