DDGS nutrient profiles showing greater variability

By Susanne Retka Schill | November 19, 2012

A recent distillers grains nutrient survey shows some change from a similar one done 10 years ago, although perhaps not as much as might be expected, given the number of ethanol plants removing corn oil. The survey was recently completed by the University of Minnesota Animal Science Department.

Devan Paulus Compart, a research assistant in the beef unit, said the average protein content was higher, at 31 percent, than the previous study which showed an average 30 percent protein. The impact of oil extraction was seen, however, in the higher protein samples, with several at 35 percent protein and the highest at 42 percent protein. While there was quite a variation in protein levels from plant to plant, she added, there was little variation within a particular plant’s samples taken during the year. 

Nutrient profiles were analyzed from 159 distillers grains samples, taken every three months for a year from 42 ethanol plants in nine Midwestern states. Wet and dry samples were evaluated. The study duplicated the methodology of one done 10 years earlier, although not necessarily gathering samples from the same plants.

In the other nutrient profiles examined, Paulus Compart said the fiber content of the distillers grains samples spanned a wide range, from 26 to 47 percent neutral detergent fiber on a dry matter basis, with the average being 34 percent. “A wide range like that is to be expected and comes from both the corn and the processing methods,” she said. Phosphorus content is up from previously reported levels. The average was 0.89 percent on a dry matter basis, with a minimum of 0.44 and maximum of 1.27 percent. The greater phosphorus content is a benefit in rations, although higher calcium supplementation will be needed to balance the minerals. The average sulfur content of the distillers grains samples was consistent with previous research.

The biggest change was the increased variability in fat content, due to ethanol plants adopting different technologies with varying efficiencies in extracting corn oil on top of variation in the concentration of solubles added to distillers grains. The fat content in the samples ranged from 5 to 14 percent with an average of 11 percent fat on a dry matter basis.

“Nutrient profiles of distillers grains are highly variable,” Paulus Compart said, adding that is likely to continue as ethanol producers adopt new technologies to improve their process. She recommends livestock feeders check the nutrient profile annually if the  distillers grains source remains the same. The nutrient profile of distillers grains should always be determined if the distillers grains source is changed, she added.