Can rapeseed lower methane emission from heifers?

Abstract

Twelve heifers were assigned to either a control diet (CON) with 26 g fat per kg dry matter (DM) or a supplemented diet (FAT) with crushed rapeseed with 53 g fat per kg DM. Methane (CH4) emission was measured by open-circuit indirect calorimetry for four days when the heifers weighed approximately 300 kg. Dry matter intake (DMI; P=0.01) and daily CH4 emission (P=0.002) were lowest on the FAT. However, CH4 emission per kg DMI (P=0.21) or per kg weight gain (P=0.44) was not different. The loss of CH4 as a percentage of gross energy intake tended to be lower on FAT (6.4%) than on CON (6.8%; P=0.08). It is concluded that the FAT may have potential to reduce CH4 emission from heifers, but further studies are warranted to document this effect.