Agroscope, 1725 Posieux, Switzerland

Protein fractions in three legume species

During the forage wilting and ensiling process, a protein degradation takes place that affects the different protein fractions. In addition to the silage conditions, secondary plant ingredients also affect the different protein fractions. In an experiment, the influence of the wilting and ensiling process on the protein fractions of the first and third cuts of the three legume species alfalfa, red clover and sainfoin was investigated. Samples of the fresh, wilted and ensiled material were analysed. Irrespective of legume type, the proportion of non-protein nitrogen (NPN, fraction A) increased significantly from the fresh to the wilted and ensiled material. The highest relative increase in NPN fraction was observed in alfalfa, where the proportion in the silage was 60 % higher than in red clover and sainfoin silage. The condensed tannins in the sainfoin and the polyphenol oxidase activity in the red clover are possible reasons for the lower protein degradation in these two species.

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