Abstract #T286

# T286
Evaluation of chemical composition and in vitro protein and fiber digestibility of corn dried distillers grains with solubles originating from seven sources.
E. Dufour*1, J. Judy1, K. Herrick2, P. Kononoff1, 1University of Nebraska-Lincoln, Lincoln, NE, 2Poet Nutrition LLC, Sioux Falls, SD.

The chemical composition and nutrient digestibility of corn dried distillers grains with solubles (DDGS) may vary by source. The objectives of this study were to characterize chemical composition and evaluate differences in digestibility of DDGS originating from 7 different dry milling facilities. Data were analyzed as a completely randomized design assuming the experimental unit was production site, which was replicated by collecting 4 independent samples over an approximate 1-mo period. Significant (P < 0.05) differences between sources were observed in crude protein (ranging from 29.6 to 31.2 + 0.32%), NDF (ranging from 29.4 to 32.7 + 0.52%), ash-free NDF on an organic matter basis (ranging from 28.98 to 32.25 + 0.53%), and crude fat (ranging from 5.53 to 7.52 + 0.27%). Rumen-undegradable protein (RUP) and its intestinally digestible fraction (dRUP) were determined according to the methods described by Ross et al. (2013). Additionally, total-tract NDF digestibility (TTNDFD) was tested using the methods described by Combs (2013) which included fermentations at 24, 30, 48, and 240 h. Significant differences (P < 0.01) in RUP and dRUP were observed across sources ranging from 65.3 to 89.1 + 2.77% of CP and 56.4 to 77.5 + 0.24% of CP for RUP and dRUP respectively. As determined by 240 h fermentations the proportion of potentially digestible NDF also differed (P < 0.01) by source and ranged from 83.0 to 86.8 + 0.40% of NDF. Greater differences (P < 0.05) were observed between sources in TTNDFD which ranged from 60.0 to 70.5 + 1.59% of NDF across sources with rate of potentially digestible NDF ranging from 4.79 to 6.82 +­ 0.48%/h. Results indicate that both nutrient composition and digestibility vary across production sites of DDGS. Fiber and protein digestibilities should be analyzed to ensure appropriate feeding and inclusion of DDGS in high-producing dairy diets for optimal performance.

Key Words: DDGS, intestinal digestion, rumen NDF digestion