Evaluation of nitrogen and organic matter balance in the feedlot as affected by level and source of dietary fiber.

Abstract

A trial was conducted to determine the effect of level and source of dietary fiber on N and OM excretion by cattle on finishing diets. One hundred twenty steers were stratified by weight and allotted to one of the following treatments: 7.5% roughage (7.5% R), wet corn gluten feed (WCGF; 41.5% of dietary DM), and all-concentrate (All Con) diet. Cattle were fed for 87 d during the summer with 23.7 m2 of pen area per animal. Steers fed the WCGF diet had heavier final weights, greater DMI, and higher ADG (P < .01) than the 7.5% R and All Con treatments. Steers fed All Con had lower (P < .01) DMI than the other two treatments. Nitrogen and OM mass balances in the feedlot were quantified. Main components were nutrient input, retention, and excretion. Nitrogen and OM intake of steers fed WCGF were greater (P < .05) than those of steers fed the other treatments. The WCGF treatment had a greater percentage of fecal N output (P < .05). The All Con treatment had a greater (P < .01) percentage of urinary N than WCGF and 7.5% R diets. Steers fed the WCGF treatment excreted more (P < .01) OM compared with the other treatments, which led to more N and OM being removed in manure at cleaning. The All Con treatment had more (P < .01) N and OM in runoff than the other treatments. Nutrition can change site of fermentation, which affects the composition of excreted material; however, total amount of N excreted may be more important than route of excretion in decreasing N losses to the environment and maximizing recovery in manure.

Performance, ruminal changes, behaviour and welfare of growing heifers fed a concentrate diet with or without barley straw

“…In this study, in which feed was offered on an ad libitum basis, the BS heifers consumed an average daily proportion of 7.9% and 8.2% of BS (DM basis), in experiments 1 and 2, respectively. Loerch and Fluharty (1998) and Bierman et al (1999) stated that all-concentrate diets fed to feedlot steers support the same growth rate, reduce dry matter intake and improve gain efficiency compared with finishing diets with 10% to 15% of roughage, on DM basis. Ruminal fermentation was affected by the diet, as expected.…”

Wet corn gluten feed and alfalfa hay levels in dry-rolled corn finishing diets: Effects on finishing performance and feedlot nitrogen mass balance1

“…Corn bran and steep are components of WCGF, and diets containing 35% WCGF contained approximately 24.5% corn bran (DM basis). Based on previous work (McCoy et al, 1997;Bierman et al, 1999;Erickson and Klopfenstein, 2001b), diets containing 24.5% corn bran exhibit reduced DM digestibility of 4.8% compared with a corn-based control diet. This reduction was applied to all diets containing 35% WCGF.…”

“…Mass balance for N was conducted as previously outlined (Bierman et al, 1999;Erickson and Klopfenstein, 2001a;Adams et al, 2004) in each of the 24 feedlot pens. Stocking density in all pens was maintained at 30.8 m 2 per steer.…”

“…Digestibility values for diets containing 0% WCGF were based upon the results of Bierman et al (1999), who reported an all-concentrate and 7.5% roughage diet to have DM digestibilities of 83.5 and 80.5%, respectively. A dry-matter digestibility of 82% was used for the 3.75% AH and 0% WCGF diet, assuming an average between 83.5 and 80.5%.…”

“…However, manure N (unadjusted for soil N) was 45% greater (P = 0.01) when cattle were fed WCGF. This is likely a result of greater OM excretion, because amount of N in manure is directly correlated to OM in manure (Bierman et al, 1999;Erickson and Klopfenstein, 2001a). When manure N was adjusted for soil N before and after the trial, treatments were not different due to variation in samples.…”