Author
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Hatfield, Ronald |
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Submitted to: Progressive Forage Grower
Publication Type: Popular Publication Publication Acceptance Date: 3/13/2015 Publication Date: 4/1/2015 Citation: Hatfield, R.D. 2015. Harvesting alfalfa leaves separately from stems. Progressive Forage Grower. April (special insert; no page number). Interpretive Summary: Technical Abstract: Alfalfa is a high-protein perennial forage with many nutritional and environmental advantages for dairy production. However, harvesting it has always been a balancing act between quality and yield due to the differences in leaves and stems. Current harvest practices to minimize total fiber (before the stem gets too mature) require cutting the alfalfa frequently (every 4-5 weeks). This creates an economic disadvantage to produce a high-quality forage because of the physical and mechanical inputs and the challenge of having enough good weather for these frequent harvests. Since most of the protein is in the leaves and the higher fiber is in the stems of the alfalfa, harvesting leaves separately from the stems would have many advantages. Several prototype machines (referred to as the “ leaf stripper”) have been constructed by the U.S. Dairy Forage Research Center in collaboration with the University of Wisconsin Department of Biological Systems Engineering. The latest prototype harvested leaves that were used in a feeding trial. Alfalfa leaves from late-bloom stage were ensiled at 22-24% dry matter, producing high-quality silage. The feeding trial used 44 first-lactation dairy cows which were randomly selected to receive two diets, one harvested under the normal early-bud stage process (Diet 1), and the other consisting of the alfalfa leaves harvested at a much later plant maturity and combined with enough stem material to provide the proper fiber content (Diet 2). Cows fed Diet 1 (leaves and stems together) were compared to cows fed Diet 2 (leaves and stem harvested separately) and monitored to determine total milk production and milk composition. Both diets produced the same level of milk production and composition. This study showed that harvesting alfalfa at later maturity by separating the leaves and stems, resulting in fewer harvests during the growing season, could produce a high-quality diet. |
