Microwave Treatment and Heat Damage Artifacts in Forages1
- C. H. Darrah,
- P. J. Van Soest and
- Gary W. Fick2
Microwave radiation has been suggested as a pretreatment to laboratory drying of freshly harvested forage samples because it quickly stops respiration. However, the effects of such treatment are not well understood. Fresh samples of both alfalfa (Medicago sativa L.) and a mixture of orchardgrass (Dactylis glomerata L.) and Ladino clover (Trifolium repens L.), as well as a dried Ladino clover forage reconstituted with water, were exposed to microwave radiation for zero to 15 min. To investigate the extent of heat damage associated with the microwave treatments, these samples were dried at 50 C and compared to material dried at 100 C. Increased levels of acid-detergent insoluble N, an indicator of heat damage, were found after only 2 min exposure in two of the three forages, and heat damage was greater as exposure to microwaves increased. It took 15 min of microwave treatment to produce heat damage in alfalfa. Drying at 100 C caused the greatest amount of heat damage in all species tested. Significant decreases in in vitro true digestible organic matter were detected only in Ladlno clover with 15 min of microwave treatment or 100 C drying. Since forages differ in their responses to microwave radiation, this drying pretreatment should be used with caution.Please view the pdf by using the Full Text (PDF) link under 'View' to the left.
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