Silage Boasts Benefits over Alfalfa Silage
By Linda McGraw
July 5, 2001
Alfalfa is still the most important
forage fed to U.S. dairy cows, but red clover may be a superior alternative.
Switching cows from alfalfa to red clover silage could help reduce manure
nitrogen levels--a benefit to the environment, according to Glen Broderick, an
Agricultural Research Service dairy
scientist in Madison, Wis.
Thats because red clover has an enzyme called polyphenol oxidase that
reduces protein breakdown in the silo. Typically, more than half the protein in
alfalfa silage gets broken down to nonprotein nitrogen (NPN) that is used
inefficiently by the cow. On average, red clover silage has only 60 percent of
the NPN of alfalfa. If not used to make milk, un-used NPN is excreted by the
Five feeding trials were conducted with cows at the ARS research farm at
Madison. In the latest two studies, cows produced the same amount of milk on
less feed: an average of 68 pounds of milk a day on 54 pounds of alfalfa dry
matter, compared with cows producing 69 pounds of milk a day on 49 pounds of
red clover dry matter. This means a 10 percent increase in feed efficiency and
a 10 percent greater energy value for cows fed red clover silage, according to
Protein efficiency was 17 percent better on red clover than alfalfa in these
last two trials. Even if this improvement applied only to the first half of
lactation, when cows are fed the most protein, nitrogen excretion would be
reduced by about 1.5 tons per year on a 100-cow dairy farm.
Red clover will now be easier for farmers to grow, thanks to new red clover
varieties developed by ARS. In the summer of 2000, ARS released newer red
clover varieties that should persist 12 to 15 months longer than older red
clover varieties. Seed will be available to farmers in about two years.
Articles about this research and 20 years of accomplishments by scientists
at the U.S. Dairy Forage Research
Center in Madison appear in the July issue of Agricultural Research magazine.
ARS is the chief scientific research agency in the
U.S. Department of Agriculture.