Feeding a bromoform-based feed additive for methane mitigation in beef cattle

Bromoform (CHBr 3 ) is a compound with strong methane-mitigating potential that binds to reduced vitamin B 12 , thereby inhibiting the cobalamin-dependent methyltransferase step of methane formation. However, bromoform is highly volatile and requires stabilization. This experiment evaluated the methane (CH 4 ) mitigating effect of feeding the Rumin8 Investigational Veterinary Product (Rumin8 IVP), a feed additive containing stabilized bromoform in an oil medium to beef cattle in a cross-over design experiment with two treatments and 10 animals, i.e., Control and Rumin8 IVP (with the active ingredient at 30 mg bromoform/kg dry matter). Methane and hydrogen (H 2 ) gases emitted were measured using gold standard respiration chambers. Rumen fluid and blood samples were collected 3 h post-feeding on the days steers exited the respiration chambers to assess rumen function and plasma biochemical parameters. On average, supplementing with Rumin8 IVP reduced CH 4 emission by 93% and CH 4 yield by 94%, and increased hydrogen (H 2 ) emission by more than 2.5-folds when compared to Control. There was a shift in the dissolved CH 4 and H 2 concentration in the rumen fluid samples consistent with the reduction in the CH 4 production and CH 4 yield. Supplementing Rumin8 IVP had no effect on feed dry matter intake or plasma biochemical parameters. Rumin8 IVP containing stabilized bromoform when fed at 30 mg bromoform/kg DMI is a promising feed additive to reduce enteric CH 4 emissions. However, further investigation is necessary to understand its long-term effect on the animal. • Feeding the Rumin8 IVP reduced methane yield by 94% in beef cattle. • Feeding Rumin8 IVP increased hydrogen production by 2.5 folds. • Rumin IVP treatment reduced dissolved methane in rumen fluid.