We are a commune of inquiring, skeptical, politically centrist, capitalist, anglophile, traditionalist New England Yankee humans, humanoids, and animals with many interests beyond and above politics. Each of us has had a high-school education (or GED), but all had ADD so didn't pay attention very well, especially the dogs. Each one of us does "try my best to be just like I am," and none of us enjoys working for others, including for Maggie, from whom we receive neither a nickel nor a dime. Freedom from nags, cranks, government, do-gooders, control-freaks and idiots is all that we ask for.
As I understand it from the enviro-wackos, it is the corn that is fed to dairy cows/beef cattle that supplies the source of the greenhouse gasses. Bovines fed a diet exclusively of roughage are said to produce far fewer amounts of greenhouse gas according to them.
So the only way way I can see them forcing down cow emissions would be to create and enforce a regulation that would restrict the grain intake of cattle. If they do that, milk and meat production would fall dramatically. If your ultimate goal is food rationing and total control of the peasants' behavior, this rule is all to the good.
As you you might expect the "eniviro-wackos" have it almost precisely backwards. Bovine nutrition is a complicated subject, but generally speaking, lower roughage, higher starch diets produce less methane than high roughage diets. Fermentation of fibre in the rumen is the main source of methane emissions in cattle. Less fibre means less emissions as long as there is enough to maintain the animals health. Further reductions occur because lower fibre diets can result in higher production of meat and milk, meaning you need less animals.
Research on this pre-dates global warming concerns, as methane was recognised as lost feed energy. Try researching agriculture or animal science sites on these subjects. Many environmentalists seem to function mostly on prejudice and rumour.
I grew up on a farm back in the 50's and early 60's. The dairy cows were put out on pasture during the summer. ( they were dry and awaiting a calf in the fall) Do not ever get behind a pasture cow...they were always quite gassy and if you added a cough to the gas it would get really ugly if you were within 15 of the aft end. I know where Jackson Pollock picked up his painting technique...he had to have spent a summer on gramps farm.