The seasonal variability of distillers grains, a byproduct of ethanol production, has been one drawback of using it in a cattle finishing ration. New research from the University of Nebraska — Lincoln is indicating that may not be the drawback the industry thinks it is.
Feeders and researchers have assumed disruptions in the supply of distillers’ grains would affect the performance of feeder cattle accustomed to the feed source. An ongoing study at UNL looks to quantify how much.
According to the research so far, it doesn’t.
“Ever since COVID, the supply and deliveries of distillers grains has been inconsistent,” said Paige Madison, a master’s student in the UNL ruminant nutrition department who worked on this research project. “We wanted to see what it would do to the cattle if producers ran out of distillers and had to pull it out of the diet and then a week later, they got a delivery and could put the full inclusion back into the diet.”
When the diet is not consistent, cattle can experience ruminal acidosis, which is when the pH of the rumen becomes low, said Jim MacDonald, UNL professor of animal science and principal investigator on this research project. “Acidosis may cause cattle to go off feed, reducing intakes and subsequently causing a reduction in average daily gain and hot carcass weight,” MacDonald said. “Rumen acidosis contributes to economic losses from reduced hot carcass weight, increased liver abscesses, and increased death loss. The economic impact of liver abscesses alone is estimated to be $41.6 million, annually.”
Distillers grains are used in feedlot diets as a source of energy and protein. Distillers can be wet, dry or modified based on the moisture of the byproduct. This research project used modified distillers grains, which have a moisture level of about 48%.
Research on variable amounts of distillers grains included in the feedlot diet can help producers manage feedlot diets for maximum efficiency and cattle health. “The current strategy to manage variable supply is to limit the inclusion of distillers grains,” MacDonald said. “We have seen the inclusion of distillers grains reduced significantly over the past decade due to an increase in the price relative to corn, a perceived reduction in the feeding value of the distillers grains, and variable supply.”
Phase one of the study looked at a ration that included distillers only at 25% of the ration. In this study the distillers grains were replaced with a blend of high-moisture corn and dry-rolled corn. Since the distillers grains also provide protein, urea was added to the control diet so the study was evaluating only the feed source to ensure cattle were not deficient in protein when the distillers grains were removed. The results of this study showed no significant differences in the performance—intake, average daily gain, and feed efficiency—between the constant versus variable inclusion groups of cattle.
Phase two focused on constant versus variable distillers at 10% and 25% of the diet, with a control of corn with no distillers. The researchers were surprised to find there was still no significant difference between the constant versus variable inclusion groups.
The research was conducted at the Eastern Nebraska Research, Extension and Education Center near Mead, Nebraska and is funded by the Nebraska Corn Board.
This winter UNL researchers started a third phase of the variable distillers grains research at UNL’s recently-opened at ENREEC’s Klosterman Feedlot Innovation Center using Hokofarm RIC2Discover technology feed bunks, which measure the pattern and amount of feed consumption by individual animals.
Instead of using just cattle performance to determine if there are differences between the constant and variable groups, phase three is also using pH probes in the rumen to detect rumen acidosis that may not result in visible symptoms.
“While we would never recommend that anyone should make sudden dramatic changes to their finishing diets, these data do provide some peace of mind that if supply disruptions or sudden changes in price occur, there is flexibility in making diet changes without negatively impacting animal performance,” MacDonald said.