HETTINGER, N.D. - Distillers grains (DDGS) has been replacing some of the corn in livestock feed, including lamb finishing rations.
“With the explosion of ethanol plants, there will be more distillers grains product available for feed,” said Michele Thompson, assistant animal scientist and Southwest Feeders coordinator at the Hettinger Research Extension Center in Hettinger, N.D. “Livestock producers are looking at DDGS as an energy alternative because of the high corn and grain prices.”
Sheep and cattle feeders would like to be able to “push the envelope” and feed higher DDGS levels, she said.
“There are concerns with how much distillers grains can be incorporated into sheep and cattle diets because of the high sulfur content,” she said.
The Hettinger Center, which is known for its sheep and lamb research, is playing a key role in finding out the maximum DDGS level that can be fed.
The Center is also studying thiamin's role in lamb finishing diets that include DDGS.
This year's 110-day lamb finishing study, which ended Sept. 2, looked at four different thiamin levels in rations containing 60 percent distillers grains for feeder lambs.
It was designed based on information gained from last year's distillers grain study that showed producers could feed as high as 60 percent DDGS, Thompson said.
In last year's study, Hettinger scientists looked at the effects of feeding DDGS at 20, 40 and 60 percent of the lamb finishing diets. All lambs in this study were fed 150 milligrams per day of thiamin.
Performance and carcass trait data didn't show negative impacts from 60 percent DDGS.
This year's study took a closer look at the level of thiamine that should be fed along with that 60 percent DDGS, Thompson said.
Some 240 spring-born lambs were fed diets composed of dried distillers grains, thiamin, alfalfa hay, corn, and a vitamin-trace mineral supplement containing ammonium chloride, along with Bovatec (an ionophore used to increase weight gain and feed efficiency).
The thiamin levels evaluated were 0, 50, 100 and 150 milligrams per day thiamin inclusion on a dry matter basis.
When feeding high DDGS in cattle, animal nutritionists have been recommending feeding 150 to 200 milligrams thiamin per head per day, Thompson said. However, in feeder lambs, up to this point, that has been an unknown, she added.
“No previous research has evaluated the effects thiamin and high distillers grain levels have on feedlot performance and the incidence of polio in fattening lambs,” Thompson said.
Polioencephalomalachia (polio or PEM for short) is thought to result from a thiamin deficiency caused by the conversion of sulfates into sulfites in the rumen, she said.
“It's a neurological disease that is characterized by dullness, star gazing, blindness, isolation, staggering, loss of motor coordination, stiffness, paddling, muscle tremors or seizures,” Thompson said.
Occasionally, the lamb will even go into a coma and die, she said.
The affected animal's brain will show a lesion in the gray matter that can be seen under a microscope if polio has occurred, she explained. That's why carcass data conducted on the feeder lambs in the study will be important.
According to Dr. Paul Plummer, staff veterinarian at Iowa State University, polio is a disease found in large numbers in feeder lambs in Iowa.
Another potential problem with feeding DDGS is that distillers grains could have a higher sulfur content than other feedstuffs due to the process of making ethanol, Thompson said.
During the ethanol manufacturing process, fermentation tanks are cleaned with sulfuric acid. The cleaning water is then added back into the byproduct before it is dried down to make distillers grains.
If too much of it gets into the byproduct, it can raise the level of sulfur in the resulting byproducts.
Sulfur toxicity can also lead to polio.
According to the National Research Council, finishing lamb diets should contain only 0.4 percent total dietary sulfur. Increasing sulfur levels above this can be a problem, possibly causing polio and sulfur toxicity.
The animal's water source is another contributor to a higher sulfur level so that also needs to be factored in when feeding DDGS.
Thompson said the Hettinger feedlot water source was tested in the spring of 2007 and contained low sulfur levels. It comes from the Southwest Water Pipeline out of the Missouri River.
“We have been amazed that we haven't seen any effects of sulfur toxicity nor signs of polio, despite the high levels of sulfur we are feeding,” she said.
The diets fed to the research lambs contain 0.69 to 0.72 percent total sulfur concentration on a dry matter basis, she said.
DDGS used in this year's study had a sulfur concentration of over 1 percent sulfur.
“This is a high level but perfect to use in this study to test our hypotheses about the effects of thiamin on polio when feeding high DDGS levels,” Thompson said.
At the Hettinger Center Sept. 2, spring-born Rambouillet and Rambouillet-Suffolk cross lambs involved in the study were alert in their pens eating the bright-gold colored dry distillers grains with the rest of the feed mix on a very cool day.
“We've been pleased with the study so far,” Thompson said on the last day of the study.
During the study, all 240 lambs gained weight, including the lambs with no thiamin in their diets.
The 84-day lamb weights taken in early August averaged 120 pounds, Thompson said. On Sept. 2, the lamb weights averaged 135 pounds, she said.
“They've done really well during the trial. Lambs have been really healthy,” Thompson said. “Their growth rate has been pretty good, averaging a half- pound a day or more.”
After 110 days, the scientists did not see any cases of sulfur toxicity or polio, she said.
The 200 lambs that reached market weight in the 110-day trial will now be shipped for harvest at Iowa Lamb Corp. in Hawarden, Iowa, located in the northeastern part of the state.
Carcass data will be collected from the slaughtered lambs to analyze the effects of thiamin and high distillers grains on carcass quality.
As well as the current feeder trial at Hettinger, a companion study to the Hettinger trial is under way at NDSU Animal Science Department in Fargo, Thompson said.
In this study, Dr. Greg Lardy's graduate student, Bryan Neville, is studying the effects of increasing sulfur and thiamin levels on hydrogen sulfide gas production in the rumen and the incidence of polio in lambs fed 60 percent distillers grain rations.
In Neville's study, lamb brain tissue will be collected at slaughter and he will look for evidence of polio lesions in the collected tissues.
Carcass characteristics will also be evaluated in the Fargo study.
Neville is using 60 spring-born lambs that are flock mates to the lambs on Thompson's study and is individually feeding them the same diets as in Thompson's study.
If both Thompson's and Neville's research projects show evidence that feeding up to 60 percent DDGS in the finishing diet does not impact animal performance or increase the incidence of polio, livestock producers would be more likely to feed higher levels of dried distillers grains.
“The true key will be what is seen in the brains of Neville's lambs,” Thompson said. “This will help us determine the actual thiamin level we need to feed in lamb diets containing higher distillers grain levels for polio prevention.”