As a cattle feeder,” observes Alan Janzen, “I have to look at what I'm faced with; what is the practical issue here?”
It's always been thus in a business where you wake up every morning with Plan A in mind and, if you're lucky, by the time you shut down for the evening, you've only revised it to Plan D, or E — for ethanol.
“The practicality in Nebraska is we've got a feedstuff we haven't completely figured out how to use,” says Janzen, owner of Circle Five Beef feedlot in eastern Nebraska at Henderson. “But we don't have a choice.”
Janzen joined a group of researchers on stage last November at the 2007 BEEF Quality Summit in Omaha to examine the beef-quality implications of feeding distillers grains (DGs) to cattle.
On both sides of the question — in the lab and in the feedbunk — the answer seems to be, when fed at moderate levels (up to 40% of the ration dry matter), DGs don't seem to have a significant effect on beef-product quality.
A look at the research
But that's not to say the effect of DGs is zero. According to Chris Calkins, University of Nebraska professor of animal science, feeding wet distillers grains (WDGs) at about 30% of the diet (dry matter) increased the concentration of polyunsaturated fatty acids in meat by about 50%. “That's a big difference,” he says.
It's also a big concern because unsaturated fats oxidize more quickly than other types of fat. And if beef from cattle fed DGs oxidizes more quickly in the retail meat case, what does that do to flavor, shelf life and color?
In Calkins' research, the impact on flavor, using beef from cattle fed even as high as a 50% dry matter diet of WDGs, wasn't significant. There was some increase in off flavor, he says, but it was very inconsistent.
However, the effect on shelf life was measurable. “The longer you're in the retail case, the more rancid the cut becomes,” he says. “That's true for all products. But to a greater extent, that oxidation is occurring in meat from cattle fed 30% wet distillers grains plus solubles (WDGS).”
The same effect was observed with meat color. After three days in the meat case, Calkins found a significant decrease in red meat color between cattle fed the 30% WDGs vs. the control group. In practical terms, he says feeding WDGs could cause the industry to give up about a day of shelf life due to discoloration.
Enter vitamin E
To see if the oxidation problem could be overcome, Calkins tried a production practice from a few years ago — feeding vitamin E. Cattle were fed 500 units of vitamin E, an antioxidant, for 100 days of the feeding period. “By feeding vitamin E over time, we overcame the oxidation problems that cause the discoloration in the retail case,” Calkins says.
“So it looks to me, if you want to feed WDGS, maybe the price of admission is including vitamin E in the diet to provide some stability for the meat products we're going to send out.”
Meanwhile, back at the feedlot
An analysis of a number of research projects, all looking at the effect of DGs on cattle performance and carcass characteristics, noted some things that cattlemen should keep in mind, says Galen Erickson, University of Nebraska Extension feedlot specialist.
“In our experiments, cattle fed (dry-rolled or high-moisture) corn gained just under 3½ lbs./day,” Erickson says. “As we added WDGs, gain increased up to 3.9 lbs./day at 40% inclusion,” then began to trail off. Feed conversion showed the same trend, improving up to 40% inclusion of WDGs before showing some decline. Marbling, outside fat and yield grade also did likewise, showing positive response out to about 40% inclusion, then trailing off.
However, dried distillers grains (DDGs) were a little different. While the gain and feed conversion responses were similar — increasing out to about 40% of the diet, then backing off — carcass quality began to decline at 40%. “So the optimum level of DDGs might be lower,” Erickson says, perhaps in the 20-30% range instead of 40% of the diet.
When combined with steam-flaked corn, however, the results were different. “When DGs replaced flakes, gains didn't increase,” Erickson says. “In fact, it was a significant linear decrease.” Feed conversions stayed flat.
Those research findings indicate a lot more needs to be discovered about the effect of DGs in feedlot diets, particularly in rations that use steam-flaked corn. Another question, Erickson says, is how do cattle feeders go past the 40% inclusion rate that seems to be the optimum?
That's important to know, Janzen says, because ethanol production has changed the entire horizon for cattle feeders. And in a very dramatic way.
Circle Five Beef has two feedlots, one at Henderson and one at Fairmont. The Henderson yard sits on the county line between two of the five most productive corn-growing counties in the nation. If all the planned ethanol plants get built in those two counties, they will use in excess of 300 million bu./year of corn.
“That will make that high corn-producing area of Nebraska nearly 100 million bu. deficient,” Janzen says, based on 2006 production. And that means he has to import corn, something he never thought would happen.
Janzen has been feeding WDGs since 1995 and is familiar with its management challenges. “We've fed mostly in that level of 25 to 40% of the dry matter in rations,” he says, until last year when he tried to contract corn and found that every farmer in his area had already inked deals with the ethanol plants. “In my mind, again being practical, I can see a time when we may have to increase the percentage of the byproduct we're feeding to offset that corn usage.”
In fact, he finished some cattle last summer on diets that were about 71% WDGs on a dry matter basis, and 85% of the ration on an as-fed basis. “Those rations only had 4% rolled corn,” he said. “I had to keep that in there to carry our liquid supplement mineral balancer.”
There are a number of concerns at that level, not the least of which is the amount of sulfur in WDGs. “We only had about three glitches in consumption that we saw throughout the feeding period. I think that can be attributed to some spikes in sulfur that we got in some of those loads. But the cattle bounced right back. The cattle finished evenly.”
Janzen's results in the feedlot mirror those of the Nebraska researchers. “I don't see any negative responses; if anything, I see some potential positives.”
However, he has seen some glitches since the packing plant increased its chain speed. Janzen averages better than 70% Choice on the cattle he sells on the rail.
“If you look at our kill sheets and track the percentage of Choice on grade and yield cattle, the week they went to six days of slaughter and increased their chain speed, we dropped about 20% in our Choice and Prime for that week in each of those three years.” That drop was significantly larger than the plant average, he says.
Janzen doesn't know why that happens, and says it's an area that needs additional research. However, he probably feeds a higher percentage of DGs than the other cattle processed in that plant, and wonders if fat from cattle fed WDGs is less saturated or less white. “Does it bloom slower and if you've got longer chill times, does that allow for better grading?”
Research has yet to yield definitive answers. Calkin's work showed no difference in the relationship between intramuscular fat content and marbling score, regardless of the level of DGs in the diet. But the research didn't evaluate bloom time, which could well be the causative factor when chain speeds increase.
Janzen thinks there are lots of areas where additional research can help answer the many questions still swirling about the effects of DGs in cattle diets. In the meantime, however, he says cattlemen have no choice but to continue adapting to ethanol-driven corn prices by pushing the limits on the amount of DGs they include in their rations.
But in so doing, he says, the industry must not lose sight of its ultimate consumer. “I think, from an industry standpoint, that old adage ‘above all, do no harm’ is real important. Because beef attracts a higher price because of its quality, we want to make sure that quality is sustained no matter what feeding system we've got.”