Effect of Cymbopogon citratus on Enteric Methane Emission, Nutrients Digestibility, and Energy Partition in Growing Beef Cattle

Methane production is a waste of energy for ruminants and contributes to greenhouse gas emissions. The objective of the present study was to evaluate the anti-methanogenic effect of increasing the supplementation levels of Cymbopogon citratus (CC) on the dry matter intake (DMI), digestibility, methane (CH4) production, and partitioning of the gross energy intake in growing beef heifers fed with a diet high in forage (68.6% forage: 31.4% concentrate). An experiment was conducted using Holstein x Charolais heifers distributed in a 4 x 4 Latin square design. The experimental treatments were: (1) control diet (CO), (2) CO + 30 g CC DM/d, (3) CO + 60 g CC DM/d CC, and (4) CO + 90 g CC DM/d. A reduction of 22.4% in methane yield (CH4 g/kg DMI) and a reduction of 21.2% in the Ym factor was observed with the 30 CC treatment (p <= 0.05). However, no significant differences (p > 0.05) were observed for the total daily CH4 production, DMI, nutrient digestibility, and gross energy intake partitioning in the heifers. Therefore, we concluded that the supplementation of 30 g CC DM/d reduced the CH4 yield without affecting the animal performance. However, the anti-methanogenic properties of Cymbopogon citratus deserve more investigation.