Pros and cons of distillers grains

University of Nebraska-Lincoln scientists reviewed nine studies regarding distillers byproducts in the beef cattle feeding industry.

The ethanol industry is expanding rapidly. This expansion in production of renewable energy also increases production of byproducts. These byproducts, primarily distillers grains plus solubles (DGS), are utilized very efficiently by ruminants. When the starch in corn is fermented to produce ethanol, the remaining nutrients (protein, fat, fiber) are concentrated three-fold.

While DGS are an excellent protein source for ruminants, the large supply and price relative to corn make DGS an attractive energy source as well. This is especially important with reduced availability and the higher price of corn because of demand by the ethanol industry.

A meta-analysis of nine experiments, where various levels of wet DGS were fed to feedlot cattle, shows that wet DGS produced higher average daily gain and gain-to-feed ratio compared with cattle fed corn-based diets without DGS. A similar analysis with dry DGS showed similar types of responses but with less apparent feeding value compared to wet DGS.

Metabolism studies suggest the fat in DGS may be partially protected from ruminal degradation, leading to a greater proportion of unsaturated fatty acids at the duodenum and greater total tract fat digestibility. Both the fat and the undegradable protein in DGS appear to explain some, but not all, of the greater feeding value of DGS compared with corn.

Lower quality roughages may be used in feedlot diets containing wet DGS because the protein, moisture and physical feeding value of DGS appears to be less when fed in finishing diets based on steam-flaked corn than in those based on dry-rolled or high-moisture corn.

The meta-analyses demonstrate that DGS have greater feeding value than dry-rolled corn; the feeding value is dependent upon level of inclusion, and wet DGS have greater feeding value than dry DGS. Low-quality roughage can be used with wet DGS, and wet DGS seem to add palatability and conditioning to the feedlot diet.
— Klopfenstein et al, 2008, Journal of Animal Science, 86:1223.

There may be a broader window for insemination times using the Co-Synch + CIDR protocol, Kansas State University researchers say.

The objective was to determine the optimal timing of insemination when using the estrus synchronization protocol, CO-Synch + CIDR, on lactating beef cows.

A total of 605 cows were treated with the CO-Synch + CIDR protocol, in which an injection of GnRH was given concurrently with a vaginally placed, progesterone-releasing controlled internal drug release (CIDR) insert. Seven days later, the insert was removed and prostaglandin was injected.

Cows were inseminated at four different times after the prostaglandin injection: 48, 56, 64, or 72 hours. At insemination, each cow received a GnRH injection to induce ovulation. Pregnancy was diagnosed 32 days following insemination. The following table is a summary of the results.

As shown above, the optimal time to inseminate appears to be 56 hours after prostaglandin administration, although 64 hours is not statistically different from 56 hours.

Researchers conclude that using a CO-Synch + CIDR protocol may have a broader window of insemination times, from 56 to 64 hours after prostaglandin.
— Dobbins, 2007, Kansas State University Beef Research Highlights.

Steers fed cracked corn during backgrounding gain faster and more efficiently during finishing than those fed soybean hulls, University of Guelph researchers find.

Scientists conducted a study to compare the effects of corn or soybean hull incorporation into haylage-based diets on backgrounding performance and subsequent finishing performance. Crossbred steers (668 lbs.) were individually fed the following diets during a 112-day backgrounding period:

• haylage, 17.5% crude protein (control),

• haylage + 20% cracked corn, and

• haylage + 20% soybean hulls.

After backgrounding, all steers were fed a high-moisture, corn-based finishing diet until they reached an ultrasound estimated backfat thickness of 0.3 in.

During backgrounding, steers fed either cracked corn or soybean hulls had significantly greater average daily gain (ADG) and gain-to-feed ratio than controls, but did not differ from one another. However, when finished on a common, high-concentrate diet, steers previously backgrounded on cracked corn had greater ADG, final body weight and ribeye area than those fed soybean hulls.

From these results, researchers suggest that the source of supplemental energy during the backgrounding period may influence subsequent feedlot performance.
— Swanson, et al, 2007, Canadian Journal of Animal Science, 87:615.