Recommendations are to begin cutting alfalfa at 750 GDD for upright silos and 680 GDD for horizontal silos. According to data collected in the upper Midwest over several years, alfalfa typically averages 38 percent NDF at 680 GDD and 40 percent NDF at 750 GDD. Filling horizontal silos with layers of alfalfa of increasing maturity will allow harvest to begin a little earlier because the layers of alfalfa are blended as the alfalfa is removed from the silo.
According to GDD, hay in Central Michigan will be ready to harvest on Monday, May 27, 2013. It is important to monitor alfalfa growth early in the growing season so that forage yield and quality are maximized for the dairy herd. To find out the GDD at your closest weather station, go to www.enviroweather.msu.edu, click the link on the top for “Field Crops”, then “Alfalfa Cutting Model” on the left side of the page. You can then select the station closest to you and track the GDD. If you need help finding the Enviro-weather station closest to you or assistance deciding when to harvest first cutting alfalfa, contact a MSU Extension educator or me at email@example.com.