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ARS Home » Midwest Area » St. Paul, Minnesota » Plant Science Research » Research » Publications at this Location » Publication #98638
Title: CHARACTERISTICS OF ALFALFA HAY QUALITY GRADES BASED ON RELATIVE FEED VALUE INDEX

Author
item KUEHN, CARLA - UNIVERSITY OF MINNESOTA
item Jung, Hans Joachim
item LINN, JAMES - UNIVERSITY OF MINNESOTA
item MARTIN, NEAL - UNIVERSITY OF MINNESOTA

Submitted to: Journal of Production Agriculture
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 8/12/1999
Publication Date: N/A
Citation: N/A

Interpretive Summary: The production of electricity from biomass would provide an environmentally friendly energy system and a new market for farmers' crops. Biomass energy has not yet developed as a viable industry because electricity prices are so low that it is not economically feasible to grow a crop and sell it for electricity production. However, a farmer cooperative in Minnesota proposes sto produce electricity from alfalfa hay and make it economically feasible by using only the stems for electricity generation and selling the alfalfa leaves as animal feed. Major unanswered questions are how much leaf material is present in commercial alfalfa hay and the nutritional value of those leaves. By sampling hays being sold at auctions we showed that leaf content of alfalfa hay is directly related to the quality grades currently used in alfalfa marketing. This means the farmer cooperative can use the existing hay marketing system to evaluate hay for purchase. We also found that nutritional value of alfalfa leaves is similar among the various hay quality grades. This means that the farmer cooperative can be confident that leaf quality will be good no matter the overall quality of the alfalfa hays that are used in the biomass energy system. This information will be extremely valuable to the cooperative as it finalizes its operating and financial planning in preparation for electricity production early in the next century.

Technical Abstract: Leaf yield and quality are of interest for alfalfa where stems could undergo a gasification process to produce electric energy, leaving leaves available for animal feed. Quality of alfalfa and grass hay is evaluated by the relative feed value (RFV) index. Hays ranked by RFV are assigned to a quality standard grade ranging from prime through decreasing quality grades sone, two, three, four, and five. The objective of this study was to determine how leaf and stem fractions varied in quantity and quality across quality hay grades. Alfalfa hay samples were collected from four commercial hay auctions. Samples were separated into stem, crude leaf, pure leaf, and weed material. Ratio of total leaf to stem material was greatest in the prime quality hay and declined as hay quality grade declined. Fiber components increased and in vitro digestible dry matter (IVDDM) decreased in quality grades from prime to grade five in stem, and crude and pure leaf fmaterial. Increases in RFV were positively correlated with increases in leaf material and leaf to stem ratio, in addition to increases in IVDDM. Commercial hay ranked as either prime or grade one quality would be the best choice of hay to be processed and fed for leaves.