PREDICTION OF NUTRIENT COMPOSITION AND IN-VITRO DRY-MATTER DIGESTIBILITY FROM PHYSICAL CHARACTERISTICS OF FORAGES

In order to develop equations to estimate nutrient composition and in vitro dry matter digestibility (IVDMD) of forages from physical charac teristics, grasses (timothy, reed canary grass and brome grass) and le gumes (alfalfa and red clover) were harvested at different stages of m aturity and analyzed for content of nutrient components, and the IVDMD and physical characteristics were determined. Physical characteristic s were used to develop multiple regression equations to estimate conte nt of nutrient components (crude protein, acid detergent fibre, neutra l detergent fibre, acid detergent insoluble nitrogen and lignin) and I VDMD for each forage. The equations for the grasses included only grin ding resistance either in linear or square terms, The regression coeff icient (r(2) or R(2)) (P < 0.05) of the equations ranged from 0.5 to 0 .94 for timothy, 0.82 to 0.93 for reed canary grass, 0.4 to 0.96 for b rome, 0.65 to 0.96 for alfalfa and from 0.71 to 0.97 for red clover. T he coefficients of regression (r(2)) between determined and estimated values for protein and IVDMD of timothy and brome grass were 0.76 and 0.59, and 0.76 and 0.66, respectively, Thus crude protein content and IVDMD of timothy and brome grass can be estimated from grinding resist ance of the forages from the respective equations.