Tri-State Neighbor: South Dakota Farm Newspaper

BROOKINGS, S.D. - Simple modifications of current management practices can sometimes lead to dramatic improvements in odor emissions from dairy farms, a South Dakota State University specialist said.

“Dietary modifications that result in reduced ammonia emissions should be considered best management practices,” SDSU Extension dairy specialist Alvaro Garcia said. “Those practices include adequately balancing diets, feeding highly digestible feedstuffs and preserving feeds adequately.”

Garcia noted that a recent study conducted by the Wageningen research center in the Netherlands studied the effect of diet on ammonia emissions from dairy cow barns. This trial also evaluated the usefulness of testing for milk urea as an indicator of emission reduction.

During this experiment, Holstein cows were housed in confinement and were fed a diet that consisted of ensiled forages and concentrates. Cows were offered rations that contained rumen-degradable protein balanced at zero, 1.1 and 2.2 pounds per cow per day.

Ammonia emissions from the barn increased with higher levels of rumen-degradable protein balance in the diet.

Bulk tank milk urea and temperature were highly correlated with ammonia emissions from the barn, accounting for 76 percent of the variation in emission.

Temperature appears to have a positive correlation with ammonia emission. Ammonia emission from the barn increased 2.7 percent when outdoor temperatures increased by 1.8 degrees Fahrenheit.

The study concluded that the emission of ammonia from naturally ventilated dairy cow barns was strongly influenced by the diet. The emission can be reduced approximately 50 percent by reducing the rumen-degradable protein balance of the ration from 2.2 to zero pounds per cow per day.

Testing for milk urea nitrogen (MUN) can be a useful and relatively inexpensive tool to monitor when rumen degradable protein is fed in excess of requirements so that the likelihood of ammonia emissions increases.

Additional odor control practices and their effectiveness can be viewed in the SDSU publication “Recommended strategies for odor control in dairy operations.” Find the publication online at this link: http://agbiopubs.sdstate.edu/articles/ESS803-D.pdf.

Comments »

Comment on this story

Comments will be approved within 48 hours