LIGNIFICATION AND IN VITRO CELL WALL DIGESTIBILITY OF PLANT PARTS

Abstract

The in vitro cell wall digestibility and chemical composition were determined with a total of 56 forage samples. Two samples each of Dactylis glomerata L., Bromus inermis Leyss., Medicago sativa L., and Lotus corniculatus L. were collected at three maturities. Two samples of Symphtum officinale L. were collected at two maturities. All samples were later separated into leaf and stem portions. Wide variation existed in chemical composition and digestibility. The range in cell wall constituents was 23.9 to 79.8%, in acid detergent fiber 16.9 to 52.3%, and in lignin 3.7 to 19.1%. The in vitro cell wall digestibility varied from 16.6 to 77.5%. Correlation coefficients between lignin content and cell wall digestibility were higher when lignin was expressed as a percentage of dry matter rather than as a percentage of cell walls. In grasses, the relationship between lignin in cell walls and cell wall digestibility was linear. However, cell wall digestibility of legumes and Russian comfrey was not as low as expected from the content of lignin.