U.S. dairy forage center presses ahead with research projects
By Heather Thorstensen
hthorstensen@agrinews.com
Date Modified: 03/17/2011 7:57 AM
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ROCHESTER, Minn.— The director of the U.S. Dairy Forage Research Center was in Rochester recently to give updates about its research projects.
Neal Martin was a keynote speaker at a meeting put on by Midwest Forage Association and the Southeast Minnesota Forage Council.
The center is USDA Agricultural Research Service's only unit dedicated to helping dairy farmers feed more forages to their cows. Research there is focused on finding ways to produce more milk from feed, especially forages, while reducing milk production's impacts on the environment.
The research farm, with 320 milk cows, is locatedin Prairie du Sac, Wis.
Dry matter analysis
Scientists are evaluating the use of near infraredtechnology as a fast, on-farm method for dry matter analysis. If farmers know the dry matter content of their forages, they can adjust for abrupt changes in dry matter to provide more consistent nutrients to cattle.
In one trial, cows were fed a mixture of corn and alfalfa silage with or without water added. Water was added to some of the silage to mimic rainfall on a bunker silo. Feed intake dropped off the first day of dry matter variation while milk yield was reduced for two days following the variation.
Bunkers
Work at the center has looked into the importance of properly packing feed in bunkers. Feed deterioration in bunkers is related to the gas in the bunker, or porosity. Packing to reach a certain dry matter density, as was recommended in the past, does not always lead to low porosity. Scientists found that porosity can be kept at low levels by packing to a bulk density, as fed,of at least 44 pounds per cubic foot.
"We think this is more usable," said Martin.
Scientists are also assessing a plastic bunker cover, known as SiloStop, that includes an oxygen barrier. One analysis found using a sealed oxygen barrier film on corn silage and haylage in a bunker can provide cost savings by reducing feed losses.
Rumen bacteria
Scientists wonder if learning more about bacteria in a cow's rumen could be key to understanding how to feed individual cows in the most efficient way.
One study selected two cows with different bacteria, then exchanged 95 percent of the rumen contents between cows. The ruminal pH, volatile fatty acids composition and bacterial community all eventually returned to pre-exchange levels. This shows the cow herself must have something to do with her own unique bacterial community.
Another study found cows with less milk fat have different bacterial communities than other cows.
Ammonia emissions
The center is looking for ways to use cow diets to reduce greenhouse gas and ammonia emissions from dairy farms. One study examined impacts of an extract from red quebracho and chestnut trees, called tannin, in cow diets. Early results show tannin helped reduce nitrogen in urine and ammonia emissions from barn floors.