US team weighs up benefits of hulless barley as dairy feed
Researchers with the Virginia Polytechnic Institute and State University (Virginia Tech) have been exploring the use of hulless barley in the diets of high-preforming dairy cattle, said Gonzalo Ferreira, assistant professor in the department of dairy science at Virginia Tech.
The trial sees the Department of Dairy Science and the Department of Crop and Soil Environmental Sciences working together.
“They have the hulless barley breeding program, and after all the development, one of the goals was to try it in livestock. We have a strong interest in finding alternative feed sources in times of high volatility in prices,” he said.
The overall findings were that the diet including hulless barley was able to support milk and milk fat production at the same levels as a corn-based diet, he said. And, even when used in a low-forage diet, the feed ingredient was not found to induce acidosis.
“Having more knowledge is a positive result, so yes this is positive,” said Ferreira. “Also it is positive – let’s say corn prices go too high, this information is useful to nutritionists so that we can provide alternative sources to corn.”
“If we think of 2012, when there was the severe drought, the price of corn grain spiked in a few months,” he said. Finding alternative feed grains that can be used in place of corn could offer feed manufactures a less expensive alternative if that situation was to repeat, he said.
From an economic point of view, the grain can be grown in a double crop system.
“It allows for a double crop with soybeans, it allows [producers] to release the field earlier than wheat allows,” he said.
The feed ingredient also needed to be evaluated because it contains less fiber and more starch than traditional, or hulled barley, he said. Hulled barley is known to ferment more quickly than corn, which can lead to issues with ruminal acidosis.
His group has completed two research projects examining the potential feed ingredient, he said. One is set to be published this spring in the Journal of Dairy Science, and data from the second experiment is still being analyzed.
The first of the two projects evaluated four diets in a group of 24 dairy cows, said Ferreira. Cattle received each of the diet for a three-week-long window before rotating to another trial feed.
The diets included different combinations of grain as the energy source, he said. The control diet included 100% corn, another diet was 100% hulless barley, and two mixed grain diets were 67% corn with 33% barley and 33% corn with 67% barley.
The team was anticipating that there would be some symptoms of acidosis starting in the cattle getting the 100% barley diet, said Ferreira. However, enough hay was added to the overall diet to reduce the possibility of acidosis occurring.
“We measured the composition of fat, and the amount of milk fat and we didn’t see any changes,” he said. “We can partially conclude it was not upsetting the cows at all.”
The team also did not expect to see that the diets would perform the way they did, he said. “We prepared this study thinking that hulless barley was going to perform not as good as corn and it performed the same way – barley performed as well as corn,” he added.
The second study compared the use of hulless barley in diets to regular barley, said Ferreira. The four diets used in the study included hulless barley with a high or low proportion of forage and regular barley with a high or low forage amount.
It again used 24 cows in a rotating system in which each group of cows received a trial diet for three weeks before changing to a new diet, said Ferreira.
“Milk production was not affected, it was the same for all diets,” he said. “We were successful avoiding metabolic issues.”
The results were somewhat unexpected, he said. “I was expecting to see at least a decrease in milk fat secretion and we did not see that, the cows ate well and performed well,” he added.
Additionally, the team has an upcoming study examining the fermentation rate of several different cultivars of barley to update the information known, he said. While there is some data on the topic from work done in other countries, this project will look at several strains of barley used in the US.