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United States Department of Agriculture

Agricultural Research Service

Title: Postharvest Changes in Alfalfa Quality

Author
item Rotz, Clarence

Submitted to: California Alfalfa Symposium Proceedings
Publication Type: Proceedings
Publication Acceptance Date: October 28, 2005
Publication Date: December 12, 2005
Citation: Rotz, C.A. 2005. Postharvest changes in alfalfa quality. Proceeding of th 35th California Alfalfa and Forage Symposium. p. 253-262.

Technical Abstract: Alfalfa losses and quality changes begin as soon as the mower contacts the standing crop, and these losses continue until the preserved feed is consumed. Harvest losses are caused by plant respiration, rain, and mechanical damage by equipment. Loss from plant respiration is relatively small when the crop is dried quickly under good drying conditions, but under slow drying conditions it can be over 10% of the crop dry matter (DM). When rain damage occurs, the resulting losses can be as much as 30% of the crop dry matter, and of course, at times the whole crop is lost. Mechanical losses increase as more machinery operations are used. For example, a typical raking operation can reduce the crop yield 5 to 10% with much of this loss being the more nutritious leaves. All of these losses, but especially respiration and leaching losses, reduce the content of digestible nutrients and increase the fiber content of the forage. These quality changes can reduce the intake and production of animals consuming the forage. Losses and quality changes are small when dry hay is stored in a shed, but when stored outside, DM losses can be 15% or more. Lost DM is protein and other highly digestible nutrients. Silage DM losses generally range from 5 to 15% depending on the type of silo used and other management practices. This loss again comes from the most nutritious portions of the forage, and much of the crop protein is converted to non protein nitrogen, which has less value to the animal.

Last Modified: 8/21/2014
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