Project Number: 6209-31630-002-18
Project Type: Specific Cooperative Agreement

Start Date: Sep 01, 2005
End Date: Aug 31, 2010

Objective:
The objectives of this cooperative research project are to (1) evaluate the effects of dietary fat concentration on the performance of beef steers fed finishing diets containing sorghum-based or corn-based distiller's grains; (2) evaluate the effects of dietary fat concentration on diet digestibility and estimated nitrogen volatilization from the pen surface; (3) evalute the effects of dietary distiller's grain on odor emissions from cattle manure; and (4) evaluate the effects of forage type on utilization of dried distiller's grains, and (5) to evaluate the effects of feeding distiller's grains on indices of sulfur metabolism and animal health in beef cattle.

Approach:
In a feeding trial, pens of beef steers (approx 400 head, avg 650 lbs) will be fed 90% concentrate steam flaked corn-based finishing diets. Treatments will be: 1) negative control diet (13% crude protein (CP), 8.25% degradable intake protein) w/no supplemental fat or distiller's grains (DG); 2) positive control diet (13% CP, 8.25% degradable intake protein) w/3% suppl fat and 0% DG; 3) 15% wet sorghum-based DG and 0% suppl fat; 4) 15% wet sorghum-based DG and 1.5% suppl fat; and 5) 15% wet sorghum-based DG and 3% suppl fat. Feed intake, animal health, animal weight gain, and carcass characteristics will be measured. Feces composition, estimated diet digestibility, and estimated N volatilization losses will be measured. One study will be performed in collaboration with 2 nutrient digestion feeding trials conducted by TAES (SCA 58-6209-6-029). The objective of the 2 metabolism trials is to determine interactions of dietary fat, wet DG, and grain processing method (DRC and SFC) on the site and extent of nutrient digestion. In Exp. 1, diets will be steam-flaked corn-based and will include 0% wet distiller's grains (WDG) and 0% added fat, 0% WDG and 3% added fat, 15% WDG and 0% added fat, 15% WDG and 1.5% added fat, and 15% WDG and 3% added fat. In Exp. 2, treatments will be 2 corn processing methods (dry rolled or steam flaked) w/0% WDG, 10% corn WDG, or 10% sorghum WDG. Feces and urine samples from individual steers will be placed in a shallow pan inside a wind tunnel. Volatile organic compounds (VOC) emitted will be trapped using sorbent tubes and analyzed using gas chromatograpy/mass spectrometry. VOC emission rates will be determined for each compound. Odor evaluations will be made by trained human olfactometry panelists. A beef cattle finishing trial will be conducted to determine the effects of distiller's grain (DG) and forage type on animal performance and manure characteristics. Forty-eight pens of beef steers (approx 480 head, avg starting weight 750 lbs) will be fed 8% forage, steam-flaked corn-based finishing diets. Treatments will be in a 2 x 3 factorial arrangement of treatments: 1) hay control diet; 2) silage control diet sorghum silage (NDF equal to sorghum hay); 3) 15% DDG and 8% sorghum hay; 4) 15% DDG and sorghum silage; 5) 30% DDG and 8% sorghum hay; and 6) 30% DDG & sorghum silage. Feed intake, animal health, animal weight gain, & carcass characteristics will be measured. Feces & manure chemical composition, estimated diet digestibility, & estimated N volatilization losses will be determined. In an additional study, 24 steers will be individually fed finishing diets containing 0, 30, & 60% wet corn DG. Liver biopsies, tissue, & blood samples will be analyzed for enzymes and metobolites involved with sulfur metabolism.