Comparisons of the In Vitro Dry Matter Digestibility of Forage Oats Grown under Different Temperatures and Light

Two experiments were conducted with forage oats to find the effects of temperature and light intensity on in v tro dry matter digestibility (IVDMD). The IVDMD of the main shoot and its component leaves and stems, showed declines with the increase in temperature.The differences in the IVDMD of leaves were caused by the temperature effects on lignification, on the rate of leaf appearance, accordingly on the age of the leaves, and on the dry matter distribution pattern among leaf positions. Higher temperature seemed to increase slightly the rate of decline in IVDMD of a leaf with aging. Stem IVDMD was influenced by true stem formation and lignin deposition at higher temperatures. With the decrease in light intensity the IVDMD of the stem of the main shoot, and, as a result, of that of the whole main shoot and that of the whole top of a plant showed slight declines.CWC content was not affected very much, but nitrogen content increased and also ADF content sl ightly increased under lower l ight intensit ies. The positive effect of light intensity on IVDMD was partly concerned with its effect on ADF content and attributable to its effect on CWC digestibility