RUP and Intestinal Digestibility of Dakota Gold

Dried distillers grains with solubles (DDGS) are often included in dairy rations to provide a source of amino acids/protein. As a result, having an accurate estimate of protein digestibility is important when formulating dairy diets. Our objective was to 1) estimate protein digestibility (ruminal and intestinal) of POET Dakota Gold and 2) compare Dakota Gold with DDGS samples from non-POET ethanol biorefineries. Method Four samples of Dakota Gold and 5 samples of a non-POET DDGS were randomly collected. All samples were sent to Dairyland Laboratories and analyzed according to the Ross protein digestibility model. This model provided estimates of 1) ruminal degradation of protein (RUP and RDP), 2) intestinal digestibility of the RUP fraction, and 3) undigested protein. Results and Discussion POET Dakota Gold had greater ruminal and intestinal protein digestibility and less undigested protein compared with the non-POET DDGS. When estimating the amount of protein supplied to the small intestine, POET provided approximately 16.26% while non-POET plants provided only 15.33%. It was also apparent that "book value" digestibility estimates for DDGS were extremely variable. Dairy NRC (2001) estimated less RUP while recent results from Dairyland Labs estimated a much greater amount of undigested protein. The combination of these results indicate that DDGS are not necessarily the same. Nutritionists need to be aware of the source of the DDGS in order to optimize animal performance and improve profitability.