Effect of morning versus afternoon cutting time on alfalfa sugar content and silage acid profile

The assessment of cutting time of morning versus afternoon has not been studied on alfalfa in the Great lakes region. This study was conducted to evaluate the effect of morning versus afternoon cutting time upon sugar content of fresh cut alfalfa and the organic acid profile of ensiled alfalfa at two different locations in Michigan. The study was conducted over 2001--2002 at the Michigan State University farm in East Lansing (EL) and Upper Peninsula experimental station in Chatham (UP), MI. Alfalfa fields were divided into sections for morning (AM, between 0900 and 1030h) and late afternoon (PM, between 1600 and 1700h) cuttings. Fresh samples were analyzed for sugar content and ensiled samples were analyzed for lactic and other organic acids. The experiment was arranged as a spilt-plot design with five replications. The sugar content of fresh samples was higher in the PM cuttings for both locations in both years. PM cut alfalfa silage resulted in increased lactic acid concentration compared to the AM cutting in only 3 out 12 cuttings for the two years at both locations. There was a significant correlation between sugar content and lactic acid concentration in the UP 2001 and EL 2002. Dry weather likely influenced both sugar content and lactic acid silage profile more than the time of cuttings during the day. Forage quality was not affected by cutting time of day.