#09-037

Complete

Date Full Report Received

10/22/2010

Date Abstract Report Received

10/22/2010

Investigation

Institution:
Primary Investigator:
The objectives of this study were to determine DE and ME content, and evaluate the effect of different particle sizes of distillers dried grains with solubles (DDGS) at a 30% dietary inclusion rate in corn diets on DM, energy, nitrogen, and phosphorus digestibility and flowability in growing pigs. One source DDGS was processed through a hammer mill to achieve of mean particle sizes of 818, 595, and 308 μm, respectively. The control diet was based on corn (96.8%), with supplemental minerals and vitamins. Three additional diets were formulated by replacing 30% of corn from the control diet with DDGS of different particle sizes. Thirty six growing pigs (initial body weight of 40 ± 1.13 kg) were assigned to 1 of 4 treatments in a randomized complete block design according to their body weight and housed in individual metabolic crates for a 9 day adaptation period followed by a 4 day total collection of feces and urine. Pigs were provided free to access water and fed an amount of experimental diets equivalent to 3% BW. Samples were analyzed for dry matter, gross energy, nitrogen, and phosphorus, and diet apparent total tract digestibility, as well as DE and ME content of corn and DDGS particle sizes, were calculated. Diet drained and poured angles of repose were measured using a modified Hele-Shaw cell method to evaluate diet flowability.

Our results confirm that adding 30% DDGS to a corn based diet reduces flowability, and grinding DDGS to 308 µm further reduces flowability compared to 594 and 818 µm particle sizes. Adding 30% DDGS to a corn based diets decreases dry matter digestibility, which will result in an increase in fecal excretion and manure production. However, for each 25 micron decrease in DDGS particle size from 818 microns to 308 microns, the ME contribution of DDGS to the diet is increased by 13.7 kcal/kg DM. If it is economic and feasible to pellet DDGS diets, the concern about flowability is eliminated and the extra energy value from using finely ground DDGS can be realized. However, if pelleting is not a viable option, and diets must be manufactured and fed in meal form, flowability may be acceptable if the DDGS particle size is greater than 600 µm, and some of the improved ME value of DDGS from a reduced particle size can be obtained. Compared to the price (e.g. $330/ton) and energy value (e.g. 7,956 kcal/kg) of choice white grease as an energy source in

grower-finisher swine diets, the difference in economic value of increased ME content for DDGS with particle size of 308 µm compared to 818 µm would be approximately $25.50 per ton of DDGS. Based on our results, DDGS particle size does not affect protein and phosphorus digestibility, so there is no additional economic or feeding value due to particle size on these economically important nutrients.