In vivo degradation kinetics of Elymus nutans from the Tibetan plateau

A digestion trial using six sheep wethers surgically fitted with ruminal cannulae was carried out to evaluate chemical composition and ruminal degradation characteristics of six wildrye (Elymus nutans) populations from Tibet. Nylon bags containing forage were incubated in duplicate for 3, 6, 12, 24, 48 and 72 h. Differences were observed in the rapidly soluble fraction, potential degradable fraction, degradation rate and effective degradability between the six populations. The rapidly soluble organic matter (OM), crude protein (CP) and neutral detergent fibre (NDF) fractions ranged from 9.76 to 21.22%, 24.27 to 34.67% and 5.93 to 12.22%, respectively. The potentially degradable OM, CP and NDF fractions ranged from 59.48 to 86.75%, 56.15 to 70.89% and 52.17 to 67.48%, respectively. The effective degradability (ED) of nutrients was also different (P < 0.01) among the altitudes. The samples collected from high altitudes had a relatively high content of CP and low content of NDF, and showed a high degradability of nutrients.