Evaluation of similar dietary roughage equivalency fed to beef steers during the growing and finishing phase

Abstract

The objective of this experiment was to determine the influence that similar dietary roughage equivalency offered in a single or two-diet system during a 210-d growing-finishing period has on growth performance, the efficiency of dietary net energy (NE) utilization, and carcass traits in beef steers. Beef steers (n = 46; initial shrunk [4%]; body weight [BW] = 281 ± 40.4 kg) were fed once daily, and bunks were managed according to a slick bunk management system across all 10 pens. Treatments included the following: 1) A single diet program that was formulated to provide 16% (dry matter [DM] basis) dietary roughage equivalency; SD) or 2) multiple diet programs (formulated to provide a dietary roughage equivalency (DM basis) of 25% for 98 d, 16% for 14 d, and 7% for 98 d; MD). Day 1 to 112 was considered the growing period, and day 113 to 210 (the day of harvest) was considered the finishing period, all steers were implanted on day 1 with a 100 mg trenbolone acetate (TBA) and 14 mg estradiol benzoate (EB) implant and implanted with a 200 mg TBA and 28 mg EB implant on day 112. Average daily gain tended (P = 0.06) to be 9.5% greater for SD compared to MD during the growing portion, and average daily gain (ADG) was greater by 11.3% (P = 0.01) for MD compared to SD during the finishing phase of the experiment. Cumulative ADG did not differ (P ≥ 0.86) between treatments (1.61 vs. 1.62 ± 0.046 kg) for SD and MD, respectively. Cumulative dietary NEm and NEg calculated based on performance did not differ (P ≥ 0.96) between treatments. There were no differences (P ≥ 0.18) detected between treatments for hot carcass weight, dressing percent, longissimus muscle area, rib fat, United States Department of Agriculture (USDA) marbling score, kidney, pelvic, heart fat, yield grade, retail yield, empty body fat, or body weight at 28% estimated empty body fat. These data indicate that feedlot producers can feed a single growing-finishing diet to beef steers with minimal effects on overall growth performance or carcass traits.

Effect of Lighter and Heavier Initial Weight on Growth Performance and Carcass Traits of Single-Source Beef Steers

“…Previous work from our lab [1] demonstrated that a single growing-finishing diet achieved a similar outcome compared to a two-diet system. The results of the current experiment show that the larger and smaller tails of a population of cattle grew at similar rates with similar rates of accretion for both protein and fat.…”

“…and (5) managing feeder cattle supply into the feedlot phase of production. Previous work within our lab group conducted by Hamilton [1] demonstrates cattle fed a single growing-finishing diet had similar growth performance and carcass traits upon harvest at equal days on feed as compared to steers fed within a two-diet phase system. However, in that experiment we used steers that were uniform in weight.…”

“…1 Average on 10/19 and 10/20/2021 BW, no shrink applied 2. Body weight captured on 12/14/2021, no shrink applied.…”

NCCC308: Nutrition and Management of Feedlot Cattle to Optimize Performance, Carcass Value, and Environmental Compatibility – Feature Collection - Nutrition and Management of Finishing Cattle

“…Enhance the utilization of carbon from energy feeds to compete in an energy economy and improve national food security ( Acharya et al, 2023 ; Coulson et al, 2023 ; Francis et al, 2023 ; Hamilton et al, 2023 ; Larson et al, 2023a and b ; Tarnonsky et al, 2023a and b ; Troyer et al, 2023 ; Wilson et al, 2023 ; Winders et al, 2023 ).…”