Some farms feed cows food that reduces methane production, but this is not effective because cows are free to roam. As an alternative, a vaccine can be used. The Pirbright Institute, located in the UK, is leading a three-year study to develop a vaccine. The effort is supported by Jeff Bezos, the Amazon founder. The vaccine should not affect the cows' health or milk. Possible solutions are selective breeding, enzymes, and genetic editing.
The study will take a long time and effort, but if it succeeds, there will be possibly an 80-90% reduction in cows producing methane.