W. A. Griffin

Comparison of Performance and Economics of a Long-yearling and Calf-fed System 1

Performance and economics of calf feeding and feeding long-yearlings was compared from University of Nebraska research conducted from 1996 to 2004. All calves in these studies were spring born and purchased the subsequent fall. The heaviest calves (292 ± 5 kg) were placed into the feedlot and fed an average of 168 d (calf-feds), whereas the lighter calves (239 ± 5 kg) were placed into a long-yearling system consisting of corn residue grazing followed by summer grazing before entering the feedlot for finishing. Long-yearlings were fed in the feedlot for an average of 90 d. At the beginning of the finishing period, long-yearlings were 143 kg heavier than calf-feds (P < 0.01). Although daily DMI was greater for long-yearlings (P < 0.01), calffeds consumed more total DM during

A meta-analysis evaluation of supplementing dried distillers grains plus solubles to cattle consuming forage-based diets 1

Data from 20 (13 pasture grazing and 7 confinement-fed) forage-based growing studies utilizing 790 steers and heifers supplemented dried distillers grains (DDGS) were analyzed using mixed models to determine the response to supplementing different levels of DDGS on gain and forage intake. Thirty-eight treatment means (442 cattle) were from grazing cattle supplemented DDGS (range: 0.00 to 1.03% BW/d). Twentyeight treatment means (348 cattle) were from confinement-fed cattle supplemented DDGS (range: 0.00 to 1.27% BW/d). Outcomes of interest were the effect of DDGS intake on forage intake (confinement studies), final BW, and ADG. In pasture grazing studies, final BW increased linearly (P < 0.01) and tended to increase quadratically (P = 0.07) with increasing DDGS supplementation. Daily gain increased linearly (P < 0.01) with increased DDGS supplementation. Results from confinement-fed studies indicate that final BW (P < 0.01) and ADG (P < 0.01) increased quadratically with increasing DDGS supplementation. Intakes measured in the confinement studies suggest that increasing DDGS supplementation increases total DMI (P < 0.01) quadratically, even though forage intake decreases (P < 0.01) quadratically with increased DDGS supplementation. Results from all studies indicate that increasing DDGS supplementation increases ADG and final BW, and supplementation of DDGS replaces some forage in forage-based diets fed to growing cattle.

Effects of Ractopamine (Optaflexx) Fed in Combination with Melengestrol Acetate on Feedlot Heifer Performance1

Two commercial feedlot experiments were conducted to determine the effects of feeding melengestrol acetate (MGA) or MGA plus ractopamine (MGA+OPT) on the performance and carcass characteristics of finishing heifers. In Nebraska (Exp. 1), 1,807 heifers (337.3 ± 20.0 kg) and in Texas (Exp. 2), 1,964 heifers (331.5 ± 6.1 kg) were fed 0.4 mg of MGA daily. For heifers fed MGA+OPT, 200 mg of ractopamine was fed daily the last 29 (Exp. 2) or 36 d (Exp. 1). Live and carcass-adjusted performance data were collected. On a carcass-adjusted basis, G:F for the entire feeding period was improved (P 0.47) between treatments in Exp. 1. Carcasses from heifers fed MGA+OPT had decreased marbling scores (P = 0.01) and greater LM area (P = 0.01) than carcasses from heifers fed MGA in Exp. 2. In Exp. 1, in which G:F was improved by 8.1%, no effect on QG was observed. In Exp. 2, in which G:F was improved by 27.2%, QG decreased. Based on these results, feeding MGA+OPT increased ADG and improved G:F, with variable effects on carcass characteristics.

Ruminally undegradable protein content and digestibility for forages using the mobile bag in situ technique

Four experiments were conducted to evaluate RUP content and digestibility for smooth bromegrass, subirrigated meadow, upland native range, and warm-season grasses. Samples were collected from esophageally cannulated cows or ruminally cannulated steers. Forages were ruminally incubated in in situ bags for durations of time based on 75% of total mean retention time, which was based on IVDMD and rate of passage calculations. One-half of the bags were duodenally incubated and excreted in the feces, and NDIN was analyzed on all bags for RUP calculations. Crude protein was numerically greater early in the growing cycle for grasses compared with later as grasses matured (P ≤ 0.32). The RUP was 13.3%, 13.3%, and 19.7% of CP for smooth bromegrass, subirrigated meadow, and upland native range, respectively. These values tended to be lower early in the growth cycle and increased (linear P ≤ 0.13) as forages matured for warm-season grasses and subirrigated meadows. Because both CP and RUP content change throughout the growing season, expressing RUP as a percentage of DM gives more consistent averages compared with RUP as a percentage of CP. Coefficient of variation values for RUP as a percentage of DM averaged 0.21 over all 4 experiments compared with 0.26 for RUP as a percentage of CP. Average RUP as a percentage of DM was 2.03%, 1.53%, and 1.94% for smooth bromegrass, subirrigated meadow, and upland native range, respectively. Total tract indigestible protein (TTIDP) linearly increased with maturity for subirrigated meadow samples (P < 0.01). A quadratic response (P ≤ 0.06) for TTIDP was observed in smooth bromegrass and warm-season grass samples. Digestibility of RUP varied considerably, ranging from 25% to 60%. Subirrigated meadow, native range, and smooth bromegrass samples tended to have linear decreases (P ≤ 0.11) in RUP digestibility throughout the growing season. The amount of digested RUP was fairly consistent across experiments and averages for smooth bromegrass, subirrigated meadow, and upland native range were 0.92%, 0.64%, and 0.49% of DM, respectively. Warm-season grasses in Exp. 2 had greater RUP (4.31% of DM) and amount of RUP digested (2.26% of DM), possibly because of cattle selecting for leadplant that contains more CP than the grasses. Forages can vary in CP, RUP, TTIDP, and RUP digestibility depending on the forage type, year, and time within year, but RUP digestibility is likely less than what previous sources have reported.

Effects of Sorting Steers by Body Weight into Calf-Fed, Summer Yearling, and Fall Yearling Feeding Systems1

ABSTRACT Two years of data (288 steers/yr) were used to determine if sorting cattle by BW into different production systems would decrease overweight carcasses (>xa0431 kg) and hot carcass weight (HCW) variation. At receiving, steers were assigned randomly into sorted or unsorted groups (n = 144 steers/group). Within a group, steers were assigned to 1 of 3 feeding times: 1) calf-fed (entering the feedlot at receiving), 2) summer yearling (grazed during winter and entering the feedlot in May) and 3) fall yearling (grazed during winter and summer and entering the feedlot in September). Unsorted steers were assigned randomly to a feeding time. Sorted steers were assigned to a feeding time based on BW, with the heaviest one-third fed as calf-fed steers and the remaining steers grazing in the winter. After winter grazing, the heaviest one-half of the remaining sorted steers were fed as summer yearlings and the lightest one-half grazed summer grass and entered the feedlot in September. On feedlot entry, steers were assigned randomly to 6 pens/treatment. This experiment was analyzed as a completely randomized design with a 2 × 3 factorial arrangement of treatments and with pen as the experimental unit. By design, interactions (P

Effect of Sorting and Optaflexx Supplementation on Feedlot Performance and Profitability of Long Yearling Steers

ABSTRACT A 2-yr study was conducted using 200 long yearling steers/yr (436 ± 30 kg) to determine the effect on performance and economics of sorting by BW at feedlot entry and feeding 200 mg/steer of Optaflexx (OPT) daily for the last 28 d. At feedlot entry, steers were allotted into 1 of 4 treatments in a 2 × 2 factorial arrangement: sorted or unsorted with or without OPT. Sorted steers were placed into 1 of 3 groups—1) heavy steers (32%; 468 kg), 2) medium steers (44%; 432 kg), or 3) light steers (24%; 399 kg) — and were fed for 97, 118, or 132 d, respectively. Initial BW for unsorted steers averaged 436xa0kg and steers were fed 111 d. There were no sorted × OPT interactions (P > 0.10) and feeding OPT did not affect steer performance (P > 0.10). Sorted steers were fed more days than unsorted steers (114 vs. 111) and were not statistically different in final BW (645 vs. 640 kg; P = 0.15) or hot carcass weight (406 vs. 403 kg; P = 0.14). Sorting increased LM area (P

Effect of Intensive Winter Management, Partial Season Grazing, and Sorting on Performance and Economics of a Long Yearling Steer Production System1

A 2-yr study (200 steers/yr) was conducted to evaluate effects of grazing management and sorting by BW at feedlot entry on performance and economics of yearling steers. At receiving, steers (247 ± 21 kg) were randomly allotted to 1 of 2 treatments: low (0.75 kg/d, NORM) or high (0.90 kg/d, INT) gains during backgrounding. After wintering, NORM and INT grazed native range for 128 and 78 d, respectively. At feedlot entry, steers were randomly allotted to 1 of 2 treatments: sorted by BW (25% heavy, 50% medium, or 25% light; SORT) or unsorted (UNSORT). Heavy, medium, light, and UNSORT steers were fed for 78, 100, 115, and 92 d, respectively. At feedlot entry, NORM was 10 kg heavier than INT (P < 0.01); however, final BW was not different (P = 0.52). Compared with INT, NORM had increased (P < 0.01) marbling scores; however, NORM had smaller LM area (P < 0.01). At the end of the winter period (P < 0.01) and at harvest (P < 0.01), NORM was more profitable. However, INT was more profitable at the end of summer grazing (P < 0.01). Sorting increased final BW (P = 0.02) due to increased days fed (P < 0.01). Sorting reduced overweight carcasses by 8.1 percentage units (P < 0.01). Sorting produced no significant difference in profitability (P = 0.13). In this study, management of steers before feedlot entry affected subsequent performance and profitability. Additionally, SORT increased final BW and reduced overweight carcasses but did not change profitability.

The effects of supplementing dried distillers grains to steers grazing cool-season meadow1

Two summer experiments were conducted with 28 (BW = 291 ± 22 kg; Exp. 1) and 48 (BW = 280 ± 22 kg; Exp. 2) steers to determine the effect of supplementing dried distillers grains plus solubles (DDGS) on growth when grazing subirrigated Sandhills meadow. Steers were stratified by BW and assigned randomly to a treatment. In Exp. 1, there were 2 treatments: nonsupplemented or 0.6% of BW (1.75 kg) DDGS supplementation daily. In Exp. 2, there were 3 treatments: 0, 0.6 (1.68 kg), or 1.2% of BW (3.36 kg) DDGS supplementation daily. In both experiments, steers were individually supplemented for the duration of the study (Exp. 1 = 92 d; Exp. 2 = 91 d). Both experiments were analyzed as completely randomized designs with individual steer as the experimental unit. In Exp. 1, ending BW (P = 0.52) and ADG (P = 0.16) were not different. In Exp. 2, ADG (P 0.06). However, in Exp. 2, supplementing DDGS to steers grazing subirrigated Sandhills meadow increased carcass weight (P = 0.02) with increasing level of DDGS supplementation. In Exp. 2, supplementing DDGS during summer grazing did not affect QG or YG. Results from Exp. 2 indicate that supplementing DDGS at levels greater than 0.6% of BW during summer meadow grazing increases ADG, with BW maintained through finishing.

The Economic Effects of Sorting Cattle by Weight and Time of Year into Different Production Systems1

A 2-yr study using 288 steers each year was conducted to determine the economic effects of sorting and feeding genetically similar cattle in different production systems. Steers were purchased at weaning in November and assigned randomly into sorted or unsorted groups. Unsorted steers were assigned randomly to 1 of 3 production systems: calf-fed steers (enter feedlot after weaning), summer yearling, or fall yearling; n = 48 steers per system yearly. For sorted steers, the heaviest third were calf fed and the remaining steers grazed cornstalks during winter. After winter grazing, the heaviest half of those steers were fed as summer yearlings, and the lightest half were fed as fall yearlings. Initial steer price was calculated using breakeven analysis for sorted calf-fed steers, and all other profits and losses are relative to sorted calf-fed steers, with a defined profit of

Finishing performance of feedlot cattle fed condensed distillers solubles

0/steer. Steer values were determined using 2007 average prices. Initial steer costs were greatest for sorted calf-fed steers and lowest for sorted fall yearlings. There were 2-way and a 3-way interaction for profit/loss. In yr 1, fall yearling gains on grass were normal, and the sorted fall yearlings were more profitable than were the sorted calf-fed steers. The reverse was true in the second year, when pasture gains of the fall yearlings were below normal. Marketing cattle on a grid decreased profit of summer yearlings because of low QG and decreased profitability of unsorted fall yearlings because of overweight carcasses. For the overall system, sorting did not increase profit on either a live or a grid-based marketing system.