Abstract :
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.
