Abstract
To determine improvement of voluntary intake of wheat straw with steam treatment, wheat straw was pressurized at 12 kg/cm^2 and steamed for 5 or 10 min. Digestion trials for measuring voluntary intake, digestibility and reticuloruminal retention time, degree of filling in total tract were conducted using wethers. Wheat straw was fed together with soybean meal (4 g/kgBW). Steam treatment improved neutral detergent fiber digestibility, however it lowered nitrogen digestibility. Voluntary intake of wheat straw steamed for 10 min. was higher than those of others. TDN content was improved by steam treatment for 5 min., on the other hand, amount of TDN intake increased with 10 min. of steam treatment. The higher TDN intake was mainly due to higher voluntary intake of steamed wheat straw. The degree of filling in total tract with feeding straw steamed for 10 min. was also higher than that with feeding of untreated straw. Reticulo-ruminal retention time with feeding of steamed straw was shorter than that of untreated straw. Moreover, the steam treatment for 10 min. tended to increase stuffed bulk density and grinding ability by cutting mill. The steam treatment for 10 min. accelerated the degradation of wheat straw in mastication and rumination. Consequently, higher voluntary intake was achieved.
