NP Rumen: Effect of a thymol-based additive on rumen fermentation, on methane emissions in eructed gas and on milk production in Holstein cowsHouda Hamdani, Najat Chami, Mounia Oukhouia, Imane Jabeur, Chaimae Sennouni and Adnane Remmal
The objective of this study was to assess the effect of a thymol-based feed additive as a means of modulating the rumen fermentation, the methane emissions and
milk production in dairy cows. The additive was made by mixing 7% thymol with 48 % of bentonite clay, 30% stevensite clay, 10% Rosmarinus essential oil
and 5% of olive oil. The first experiment was to evaluate in a rumen in vitro system the effect of different concentrations of the additive on gas production. In
the second experiment, the additive was fed to Holstein dairy cows to test the effect on the emission of methane and milk production. Total gas production and
percent methane in the gas in the in vitro rumen incubation was reduced curvi-linearly by increasing concentrations of the thymol additive. Supplementing the
diet of lactating Holstein cows with 100 g/d of the additive reduced methane in eructed gas by 33% and increased milk production by 10%.
