Abstract
Pure swards of orchardgrass Phyllox, Kitamidori and St. Hokkaido, were harvested at the stages of maturity during first growth in the spring, and in the subsequent regrowth. Each batch of harbage was fed to 5 wethers ad libitum and a digestion trial was conducted. Forage and feces density were determined by MONTGOMERY'S method to get relationships between digestibility and physical form. The results are summarized as follows: 1. Dry matter digestibility (DMD), TDN and digestible energy (DE) contents of aftermath in summer (summer grasses) were lower than those of first cutting grasses in spring (spring grasses) and of aftermath of last cutting of the year in autumn (autumn grasses). 2. First cutting grasses showed the fall in digestibility and voluntary intake with increasing maturity. Intake of DE/dry/kg. W^<0.75> and nutritive value indexes of spring grasses and autumn grasses were generally higher than those of summer grasses. 3. Digestibility of cell wall was depressed much more at high intake than digestibility of cell contents. 4. Significant negative correlation was observed between the contents of cell wall in aftermath and its density, and same correlation was observed in feces. DMD of grasses had significant effect on feces density.
