One hundred twenty crossbred beef steers averaging 377 kg were used in a 2 x 4 factorial experiment to determine the dose-response effects of recombinant bovine somatotropin (rbST) implants on growth performance and carcass characteristics. The implant dosages were 0 (sham), 40, 80, or 160 mg/wk administered s.c. in the tailhead region on a weekly basis throughout the experiment. The steers were fed a high-concentrate diet, which contained either a degradable (DP; soybean meal) or an escape (EP; corn gluten and blood meal) protein source. No dietary protein effect or dietary protein x rbST level interactions were detected. Recombinant bST decreased both DMI (P less than .10) and feed/gain (P less than .05) in a linear dose-dependent manner. Dosage of rbST did not significantly affect (P greater than .10) ADG or final weight of the steers. Recombinant bST decreased backfat depth (P less than .10), marbling score (P less than .05), and quality grade (P less than .10) and increased yield grade (P less than .10) in a linear dose-dependent manner. Soft tissue composition of the 9-10-11th rib section was altered (P less than .01) by rbST administration in a linear dose-dependent manner. The percentage of protein in the rib section was increased by 9.4% and fat was decreased by 11.8% at the 160 mg/wk rbST level compared with the sham-implanted steers. Recombinant bST did not affect (P greater than .10) dressing percentage, hot carcass weight, kidney, pelvic, and heart fat, or longissimus muscle area.(ABSTRACT TRUNCATED AT 250 WORDS)
We conducted two experiments to determine the feeding value and effects on diet digestibilities, passage rates, and ruminal metabolism of wheat middlings (WM) fed as a replacement for either the concentrate or roughage components of finishing diets of steers. In Exp. 1, 120 medium-framed steers were blocked by weight and randomly allocated to one of six treatments of high-concentrate diets: control (0%); 5, 10, or 15% pelleted WM replacing dry-rolled corn (DRC); and 5 or 10% pelleted WM replacing chopped alfalfa hay (ALF) components of the diet. Increasing WM replacement of DRC increased DMI (P < .01) and feed:gain ratio (FG; P < .05) linearly. A 9.2% increase in daily DMI and 10.1% increase in FG were observed at 15% of WM. Daily gain and final weight of the steers were not influenced by WM replacement of DRC. The WM replacement of ALF decreased (P < .01) daily DMI linearly, but it had no effect on ADG, final weight, or FG. In Exp. 2, six medium-framed steers, fitted with ruminal cannulas, were used in a 6 x 6 Latin square design with the same treatments as described in Exp. 1. Dry matter, OM, and starch digestibilities decreased (P < .01) by increasing replacement of DRC with WM, and replacing ALF increased DM and OM digestibilities linearly (P < .01). Wheat middlings could replace only up to 5% of DRC without reducing feed conversion efficiency and diet digestibilities, but complete (100%) or partial (50%) replacement of ALF increased digestibilities of DRC finishing diets.
Sonon, R.N.; Dalke, B.; Pope, Ronald V.; Riley, Jack G.; and Laytimi, A. (1992) Evaluation of inoculant and NPN silage additives: a summary of 26 trials and 65 farm-scale silages AbstractResults from 26 trials comparing fermentation, dry matter (DM) recovery, and effects on cattle performance of inoculated or nonprotein nitrogen (NPN)-treated silages vs. controls were summarized using paired t-test analysis. Inoculants consistently improved fermentation efficiency, DM recovery, feed conversion, and gain per ton of crop ensiled in both corn and forage sorghum silages. The use of NPN, particularly urea or anhydrous ammonia, adversely affected fermentation efficiency, DM recovery, avg daily gain, and gain per ton of crop ensiled, particularly for the higher moisture forage sorghums. SummaryResults from 26 trials comparing fermentation, dry matter (DM) recovery, and effects on cattle performance of inoculated or nonprotein nitrogen (NPN)-treated silages vs. controls were summarized using paired t-test analysis. Inoculants consistently improved fermentation efficiency, DM recovery, feed conversion, and gain per ton of crop ensiled in both corn and forage sorghum silages. The use of NPN, particularly urea or anhydrous ammonia, adversely affected fermentation efficiency, DM recovery, avg daily gain, and gain per ton of crop ensiled, particularly for the higher moisture forage sorghums.
One hundred twenty medium-framed steers were fed one of six high (90%) concentrate rations: control (0), 5, 10, or 15% pelleted wheat middlings (WM) replacing the concentrate (dry rolled corn) and 5 or 10% pelleted WM replacing the roughage (chopped alfalfa hay). Increasing WM replacement of the concentrate increased both dry matter (DM) intake and feed/gain ratio linearly, without influencing daily gain or final weight. WM replacement of the roughage decreased DM intake linearly, but it ha d no effect on daily gain, final weight, or feed efficiency . The data indicate that WM could replace only 5% of the concentrate without reducing cattle performance, but complete (100%) or partial (50%) replacement of the roughage with WM had no adverse effect on cattle performance. The pelleted wheat middlings were provided by ADM Milling Co., Shawnee Mission, Kansas. SummaryOne hundred tw enty medium-framed steers were fed one of six high (90%) concentrate rations: control (0), 5, 10, or 15% pelleted wheat middlings (WM) replacing the concentrate (dry rolled corn) and 5 or 10% pelleted WM replacing the roughage (chopped alfalfa hay). Increasing WM replacement of the concentrate increased both dry matter (DM) intake and feed/gain ratio linearly, without influencing daily gain or final weight. WM replacemen t of the roughage decreased DM intake linearly, but it ha d no effect on daily gain, final weight, or feed efficiency . The data indicate that WM could replace only 5% of the concentrat e without reducing cattle performance, but complete (100%) or partial (50%) replacemen t of the roughage with WM had no adverse effect on cattle performance.
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