Saskatoon, Saskatchewan
October 20, 2003

Researchers are making major progress toward building a better barley for feedlot cattle with a new effort toward "slow DMD" barley varieties, says Dr. Brian Rossnagel of the University of Saskatchewan Crop Development Centre.

The key trait in the potential varieties is a slower rate of dry matter disappearance (DMD,) says Rossnagel, whose effort is supported in part by producers through the Barley Check-off Fund, administered by Western Grains Research Foundation (WGRF.)  Feeders often refer to barley as "too hot" - its rapid digestion can lead to the twin problems of acidosis and bloat, which can reduce feed intake and weight gain. But cattle fed slow DMD barley digest the grain more slowly, reducing the buildup of volatile fatty acids and gases that cause these problems.

"Slow DMD barley will allow cattle to maintain feed intake at a higher level," says Rossnagel. "As a result, we estimate a significant improvement in barley's feed-to-gain ratio. We're just getting started with this material, so the first registered variety will likely be five to seven years away, but our chances of success are quite promising. It looks like there is good potential for improving this trait."

Cattle feed is arguably the most important end use of barley on a volume basis - 80 percent of total barley production is ultimately used as feed, with 75 to 80 percent of this used by cattle, says Rossnagel. But the complexities of the rumen environment have made it extremely difficult for incremental grain improvements to have any impact on animal performance. Now, a rise in the power of science and in screening technology has widened the opportunity for identifying beneficial nutritional and digestibility characteristics, and incorporating these into new varieties.

The slow DMD trait was first identified and bred into new barley varieties by researchers at Montana State University (MSU), which has released the variety Valier, the first North American variety bred specifically for slow DMD. "The slow DMD trait appears to be well expressed in Valier, but the agronomics of the variety aren't well suited for Canadian production," says Rossnagel. "At the Crop Development Centre, we have a long-standing relationship of sharing material with MSU, and we are now using some of their material along with other germplasm to develop slow DMD varieties for Western Canada. 

The Crop Development Centre has made several initial crosses with Valier and is also working with material from the world barley germplasm collection, which shows an even slower rate of dry matter disappearance.

"The starch in all cereal grain is held in the kernel in a protein matrix, which is broken down in the digestive process," explains Rossnagel. "Slow DMD barley has a different starch-protein matrix structure compared to a traditional barley such as Harrington. If you take Harrington and roll it, the result is a relatively powdery substance with very exposed starch granules - the rumen enzymes can digest this really fast. With slow DMD barley, as with corn, this rapid digestion is much less likely to happen because the starch is held more tightly in its protein matrix.

"Slow DMD barley will not completely eliminate acidosis and bloat problems, but it should greatly reduce them."

More information on this topic is available in the latest WGRF Industry Report newsletter, which focuses on "Building a better feed barley for cattle." The Industry Report is available on the WGRF Web site, www.westerngrains.com.

The Barley Check-off Fund allocates approximately $600,000 annually to barley breeding programs. The Fund is administered by Western Grains Research Foundation, based on an annual check-off of $0.40/tonne, deducted from Canadian Wheat Board final payments to producers in Saskatchewan and Manitoba.