Effects of dried distillers grains with solubles on growing and finishing pig performance in a commercial environment.

Three experiments were conducted to determine the optimal level of dried distiller grains with solubles (DDGS) from a common ethanol manufacturing facility and to determine the potential interactions between dietary DDGS and added fat on performance and carcass characteristics of growing and finishing pigs. All experiments were conducted at the same commercial facility and used DDGS from the same ethanol manufacturing facility. In Exp. 1, a total of 1,050 pigs (average initial BW 47.6 kg), with 24 to 26 pigs per pen and 7 pens per treatment, were fed diets containing 0 or 15% DDGS and 0, 3, or 6% added choice white grease in a 2 x 3 factorial arrangement in a 28-d growth study. Overall, there were no DDGS x added fat interactions (P >/= 0.14). There was an improvement (linear, P < 0.01) in ADG and G:F as the percentage of added fat increased. There was no difference (P = 0.74) in growth performance between pigs fed 0 or 15% DDGS. In Exp. 2, a total of 1,038 pigs (average initial BW 46.3 kg), with 24 to 26 pigs per pen and 10 pens per treatment, were fed diets containing 0, 10, 20, or 30% DDGS in a 56-d growth study. Pigs fed diets containing DDGS had a tendency for decreased ADG and ADFI (both linear, P = 0.09 and 0.05, respectively), but the greatest reduction seemed to occur between pigs fed 10 and 20% DDGS. In Exp. 3, a total of 1,112 pigs (average initial BW 49.7 kg), with 25 to 28 pigs per pen and 9 pens per treatment, were used in a 78-d growth study to evaluate the effects of increasing DDGS (0, 5, 10, 15, or 20%) in the diet on pig growth performance and carcass characteristics. From d 0 to 78, ADG and ADFI decreased linearly (P </= 0.04) with DDGS level, but the greatest reduction seemed to occur between pigs fed 15 and 20% DDGS. Efficiency of gain tended to improve (P = 0.06) when DDGS were included in the diet. There was no effect of DDGS (P = 0.22) on loin depth. Carcass weight and percentage yield decreased (linear, P </= 0.04) with increasing levels of DDGS in the diet. Backfat and fat-free lean index tended to decrease (linear, P </= 0.09) with increasing levels of DDGS in the diet. In conclusion, finishing pigs raised under commercial production conditions can be fed 10 to 15% DDGS from the source evaluated in this study before growth rate is compromised.