The purpose of Present study was conducted to evaluate the effects of adding essential oils (Ziziphora clinopodioides and Mentha pulegium) on alfalfa silage on the rumen degradation parameters with in vitro technique. Present study was performed by utilizing an in vitro gas production method at various incubation intervals. Rumen fluid taken from three lactation, rumen-fistulated Holstein cows. The gas production rate was measured at standard times from 0, to 96 hours. The outcomes of this experiment show that Ziziphora clinopodioides and also Mentha pulegium essential oils had a positive influence on gas production rate. Silage content with Mentha pulegium had more decrease effects than Ziziphora clinopodioides in Gas production compare with control silage and it was significant. Gas production values (at 96 h incubation) in silage with no added essential oils, 30ML of Ziziphora clinopodioides and 30ML of Mentha pulegium were 68.82, 56.12 and 49.74, respectively. Compared with control, aerobic stability had a significant difference and it was developed in silage treated with essential oils. The findings of their findings showed that these essential oils could be used to increase the performance of ruminants. In addition, adding essential oils could change the rumen fermentation in ruminant, however, more research is still needed to proving this conclusion.

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