ASSESSMENT OF CONTENTS OF STRUCTURAL CARBOHYDRATES AND LIGNIN OF PERENNIAL FODDER HERBAGES DEPENDING ON VEGETATIVE STAGE GROWTH

The purpose of this study is to evaluate cereal grasses – Bromus inermis, Festuca pratensis, Phleum pratense, and legumes: Trifolium pratense, Medicago varia in terms of their content of acid-detergent fibre (ADF), neutral detergent fibre (NDF), acid-detergent lignin (ADL) and hemicellulose (HC), cellulose depending on phases of vegetation – grasses: at vegetative, earing and flowering; legumes– vegetative. It was found that as the herbs grow, an increase in all fractions of the cell walls of leguminous herbs is observed, the cell walls occupy a smaller fraction of dry matter than in grasses, due to the lower HC content in them –10-12%, compared with 25-30% in grasses. The contents of ADF, NDF and ADL (% of dry matter) in grasses prior earing are 31-31, 50-55, 4-6: in earing – 32-37, 55-65, 5-6; in flowering – 40-45, 65-70 and 70-72, 7-9, respectively. Legumes have a higher content of ADL. As plants grow, the relative proportion of ADF in NDF increases, but it does not exceed 50% in grasses. In legumes – 70-80% regardless of the growth phase, explains the lower digestibility of legumes than grasses. To judge the levels of ADF and NDF in herbs, depending on the content of crude fibre (CF), the corresponding regression equations were calculated for grasses and feed prepared from them. The relationship between CF and ADF was closer (n = 64, s = 2.4%, r = 0.93) than between CF and ADL (n = 64, s = 4.4%, r = 0.87). Based on these studies and generalisation of the literature data, ADF and NDF in hay and haylage standard are recommended.