Recently I have had the opportunity to work with one of Kentucky’s unique, well-known industries. As with anything, this stemmed from a desire, or rather a necessity, to learn the local lingo. Slop, wet cake,distillers grains, and bourbon all come together in this industry to which I am referring. Having experience with fuel ethanol wet distillers grains derived from corn, my experience with bourbon distillers grains was zero. Tommy Yankey, Anderson County Extension Agent, and I have been able to get a look behind the scenes at a couple of bourbon plants on the Bourbon Trail to increase our knowledge and understanding as to what processes are involved in converting grains to alcohol as well as the residue that makes its way back on to many Kentucky farms as livestock feed. We’ve been able to set up a short feeding
demonstration with Glenn Williams, Laurel County Extension Agent, as well as a storage demonstration in Anderson County due to collaborations with the bourbon industry and those involved with marketing the spent grains. I’ve come to realize that Kentucky may have a gold nugget in this regional feed source if we can overcome a few logistical challenges.
The recent fuel ethanol industry boom is based primarily on corn in much of the US. The distillers grains that come from this industry are a high quality feedstuff with conventional wet distillers grains having actually a slightly higher energy value than corn. Researchers at the University of Nebraska recently reported that wet distillers grains has 130% the energy value of dry-rolled corn when fed to growing cattle on a 70% forage diet (Nuttelmann et al., 2009 Nebraska Beef Cattle Report). Previously, researchers from Nebraska had reported that wet distillers grains were 128% the energy value of corn when fed to calves and 169% when fed to yearling cattle compared to dry-rolled corn in finishing diets (Larson et al., 1993, J. Anim Sci.). Other researchers have also indicated that the energy content of wet distillers grains may be greater than corn, but there is variability depending on the nutritive quality of the distillers grains, level fed, and the diet composition.
Bourbon wet distillers grains are derived from a grain bill that is predominately corn, but other cereal grains such wheat or rye may be used along with malted barley. Barley distillers grains has been shown to have lower digestibility than other small cereal grains due to the husk of the grain (Mustafa et al., J. Sci. Food Agric., 2000). Preston updated a table of the nutritive value of various feedstuffs which was published in Beef Magazine in 2009 reporting dried barley distillers grains having 77% TDN with dried distillers grains derived from corn being 99% TDN and corn listed at 88% TDN. The energy values were approximately 70-75% for the barley distillers grains compared to that of the corn distillers grains. This simply illustrates that not all distillers grains are the same.
In Table 1 nutritive values for samples from our demonstration projects are presented along with values for wet distillers grains derived from corn as reported by Kaiser in 2005. Samples collected from a few of the distilleries in our demonstration work have come back containing 82-84% TDN. Holt and Pritchard in 2004 reported dry matter and crude protein levels of 31% and 36%, respectively for corn-based wet distillers grains. Bourbon distillers wet grains are very similar to that of corn-based fuel ethanol plants from a nutrient profile, but dry matter content can vary dramatically depending upon the plant and process
being utilized to separate the thin stillage or slop from the grains. It is expected that the energy value will be slightly lower than that of corn-based ethanol distillers grains due to the malted barley and lower digestibility of the barley husk. Preston reported corn to have an NEm and NEg of 0.98 Mcal/lb and 0.65 Mcal/lb which is essentially identical for the wet bourbon distillers grains samples we’ve submitted. It is important to keep in mind that the chemical analysis does not equate exactly to performance. In other words, the biological value may be greater or lower than what is reported on paper. A good example of this is soyhulls. The typical TDN and energy values often reported are less than that observed when fed to cattle on a high grain diet. On paper, however, the bourbon wet distillers grains have a reported energy value similar to that of corn.
So what have I tried to lay the ground work for in the above paragraphs? First, wet distillers grains, fuel or human consumption derived, is both an energy and protein source in cattle diets. Secondly, wet bourbon distillers grains has a nutritive value quite similar to reported values for wet distillers grains derived from corn-based ethanol with an expected energy value that may be slightly lower. Kentucky has a great local feed source available for beef cattle producers and in the future we’ll discuss how one might utilize this regional feed source in cow and growing / finishing diets. In the mean time, keep your fences mended and look towards the sky for rain.
Source: Dr. Jeff Lehmkuhler, Extension Beef Cattle Specialist, University of Kentucky