In this study, an in vitro rumen gas production technique was utilized to evaluate the effect of thyme methanolic extract (0 and 1 ml/30ml buffered rumen fluid) on degradability of sunflower meal. The feed sample(200mg sunflower meal plus extract were incubated with rumen liquor taken from three fistulated talesh cow at 2,4,6,8,12,24,48,72 and 96h. result show that gas production was reduced (p<0/05) on addition extract of Thyme. Result showed that extract of thyme decreased water soluble fraction (a), the slow degradable fraction (b), the potential degradability (a+b) and increased degradation rate of the slow fraction(c). This study suggested that thyme extract have the potential to affect fermentation efficiency.
