For decades, they depended on corn as the primary feedstuff for their livestock. Then the ethanol boom hit, and the price of corn skyrocketed to previously unimaginable levels—nearly $8 per bushel in some parts of the country in 2008. As the price went up, profit margins went down, and the industry found itself at an impasse. It was a scenario that made finding new ways to feed cattle increasingly crucial. “Co-products” became the new buzzword as distiller’s grains from corn ethanol production and beet pulp from sugar refining began to replace grain in animal’s diets.
As co-products took many forms—beet pulp pellets, wet beet pulp, wet distiller’s grains, dry distiller’s grains—storing and transporting them became its own science. Wet products need to be used locally and have a short shelf life. Dry products lose nutrient value. The intricacies and options are complicated. But as with most agricultural problems, new research is always on the horizon.
A recent study conducted by the South Dakota State University Dairy Department has explored ensiling ethanol wet distiller’s grains (WDG) with various other feedstuffs to increase shelf-life, and found not only did it stretch the WDG, but offered increased nutritional benefits as well. One of those feedstuffs was wet beet pulp.
The study set out to evaluate fermentation and preservation characteristics of blends ensiled on as as-fed basis by comparing 100 percent beet pulp (BP), 67 percent BP: 33 percent WDG, and 33 percent BP: 67 percent WDG. The study addressed storage issues, nutrient value and effects on milk production.
On its own, distiller’s grains can make an excellent feed additive for ruminants because it can supply about 10 percent more energy, 30 percent more protein, 10 percent more fat and 1 percent more phosphorous than corn alone. But, when fed with other feeds, there are risks of excess nitrogen and phosphorus in manure, an environmental concern; and excess protein in the diet, resulting in too much sulfur and the risk of thiamin deficiency or hydrogen sulfide toxicity, which can cause neurological disorders. The experts recommend distiller’s grains be fed with dietary ingredients low in protein, fat and phosphorous. Beet pulp often fits that bill, as it is low in those elements, yet provides fermentable energy due to the presence of highly digestible carbohydrates. Beet pulp also increases acetate production in the rumen, reducing the risk of acidosis.
“The blends are lower in sulfur than the original co-product,” says SDSU Beef Extension Specialist Cody Wright, “but it can still be a problem.” He emphasizes testing the product for exact nutrient content in order to monitor protein and sulfur intake.
The combination can take varying forms. Dry distiller’s grains, because of its high fat content does not pellet well. But when combined with dry beet pulp, it not only forms a nutritious pellet, but a sturdy and palatable one.
Wet distiller’s grains need to be fed within a few days, limiting their use to producers within close proximity to ethanol plants. If that is not possible, it needs to be ensiled. The SDSU study addressed the option of ensiling the co-product with various substances, wet beet pulp, corn silage and soy hulls, and found both nutritional value and aerobic stability were increased.
Successful ensiling of wet beet pulp (WBP) with WDG depends on the same elements as any other product—air exclusion, adequate compaction, and low pH. Initial pH levels were highest in straight WBP and decreased with each level of WDG, ranging from 4.2 to 3.3.
Acetic acid increased over time in all combinations, but decreased with WDG content, with 100 percent WBP showing the highest levels (5.17 percent of dry matter).
The study concluded WDG and WBP preserve very well when blended together, increasing the life of both products. That’s especially good news for producers not in close proximity to co-product sources, who need to make WDG last longer; or for those who cannot utilize an entire truckload in a timely manner. It also helps those who depend on regular deliveries, as the increased shelf life can cover the gap when supply is interrupted. Wright says the key to storing co-product combinations is keeping the moisture content of the final product at a minimum of 50 percent.
On the dairy side of the equation, the results were also promising. Tests showed the blends provide effective fiber and retain the ability to sustain milk fat. Milk yield and feed efficiency were best with the 33 percent WBP blend, while the 67 percent WBP blend produced better milk fat and milk protein. Overall, the researchers concluded the cows fed the 33 percent WBP: 67 percent WDG mixture fared the best with more total milk, slightly better feed efficiency and higher milk protein yield. They recommended the blend be used as 24.6 percent of the diet dry matter.
The research opens up a new range of possibilities in feeding and storing both corn ethanol and sugar co-products, helping to increase profit for all sectors of ag production, from beef and dairy to corn and sugar.