Abstract: Three rumen fistulated Xinjiang Kazakhstan rams were applied as experiment animals to compare ruminal degradation kinetics of lavender hay before and after essential oil extraction using a nylon bag technique. The hays placed in nylon bags were incubated with duplicate for 6, 12, 24, 36, 48 and 72 h in the rumen of each ram. No obvious differences between essential oil unextracted and extracted lavender hay were observed for crude protein, neutral detergent fibre and acid detergent fibre, the rumen disapperance rates of DM and CP decreased significantly after the essential oil extracted (P<0.05). Although the rapidly degradable portion a value and slowly degradable portion b value did not differ between unextracted and extracted lavender hays (P>0.05), the degradation rate c and effective degradability values for DM and CP were significantly lower in the extracted hay than the unextracted hay (P<0.05), and such results might be due to greater contents of vanillic (26.5%), protocatechuic (33.3%) and ferulic acids (24.8%) occurred in the oil extracted hay. In summary, essential oil unextracted lavender hay exhibited high nutritive value in term of rumen degradation rate.

Key words: lavender hay; rumen degradation rate; nylon bag technique