The Effects of Rosemary and Thyme Medicinal Herbs Consumption and Their Essences on Gas Production and Rumen Fermentation Parameters in Dairy Cows Under in vitro Conditions

The aim of this study was to investigate the effects of two medicinal plants of thyme and rosemary and their essences on gas production, digestibility, ruminal fermentation  and methane production parameters.  The gas production test was conducted with a 96-hour cultivation time in the form of a completely randomized design, along with four repetitions per treatment. The treatments consisted of: 1) basal diet with -  a forage-to-concentrate ratio of 50:50 without addition of the medicinal herbs and essences as the control treatment; 2) control treatment + 15 g/kg of thyme; 3) control treatment + 15 g/kg of rosemary; 4) control treatment + 100 mg/kg essence of thyme and 5) control treatment + 100 mg/kg of rosemary essence.The results of this study indicated that the application of the essences caused a significant increase in the gas production potential from the fermentable segment (b) and the gas production rate constant (c) compared to the control treatment (P <0.05). The treatments containing essences increased dry matter digestibility, organic matter and total volatile fatty acids and propionic acid as compared to the control (P<0.05).  Methane production in milliliters per gram of dry matter and ammonia nitrogen decreased remarkably in all experimental treatments compared to the control treatment(P<0.05). Overall, according to the results of this study, it seems that changes to the ruminal fermentation processes are possible by using the herbs and their essences, although additional –experiments  are - needed to investigate these effects.