Chemical composition, mineral content, "in vitro" gas production and relative feed value of Betonica bulgarica Degen et Neic.

Chemical composition and mineral content of biomass from four populations of Betonica bulgarica Degen et Neic. were determined. The average crude protein content in the biomass was 77.41 g.kg(- 1) of dry matter (DM); crude fat - 7.77 g.kg(-1) DM; crude fibre - 260.16 g.kg(-1) DM; ash - 50.47 g. kg(-1) DM and nitrogen free extracts (NFE) - 604.19 g.kg(-1) DM. The content of nitrogen, calcium, phosphorus and magnesium in the biomass of B. bulgarica was close to the meadow grasses. The content of potassium is lower. The content of sodium, iron and manganese was significantly lower. Structural fibre components were an average for neutral detergent fibre (NDF) 44.82 % and acid detergent fibre (ADF) 39.93 % close to that of alfalfa and legume grasses. "In vitro" gas production of B. bulgarica biomass at 24 hour was average 257.55 dm.ml(-1) and at the 48 hour - 270.35 dm.ml(-1) (CO2 and CH4), which is close to the group of legume and cereal meadow grasses. The relative feed value (RFV) of B. bulgarica biomass is close to perennial legumes and exceeded alfalfa (Medicago sativa L.) with 6 to 33 %. Regression equations were developed for advanced determining the quantity of gas production at 24 and 48 hours through the metabolizable energy (ME), MJ.kg-1 DM and the Relative feed value through the neutral detergent fibre.