I dunno, I'll have to do my own research on this one, my third cousin's dog walkers nephew's barber said he read a tweet declaring they were actually the same animal, just one ate more as a youth and has an accent due to the weight.
Look at how much calories a horse needs per day, and then look at how much CO2 gets emitted to produce said food. Even the amount of CO2 a horse exhales per day is already significant.
Tldr: cows in sheds eating corn is the problem, cows eating natural grass actually sequester more carbon than an empty field.
Long answer:
Photosynthesis can only get carbon from the atmosphere. This carbon is then turned into plant material in grass. This grass is then eaten by the cow. A small portion of this grass will be converted into methane and other byproducts in the cow's digestive tracks. Some will be turned to energy for the cow and a vast majority will be shit out as raw unprocessed material. This raw unprocessed material, i.e. cow shit, this will last in the environment sequestering more carbon for longer time than just grass sitting there by itself. A grazed paddock will grow more grass than a non-grazed paddock because the cows are eating the fucking grass. i.e. more carbon from the environment is getting sequestered in the grass and the cow shit.
The only reason that cows get such a bad wrap is that variouse other factors are being counted that really shouldnt be under cows. Deforestation to grow plants to feed livestock, the transportation of meat, livestock feed etc etc.
A properly managed grass fed beef (like what we have here in australia) actually has a net negative effect on ghg. The factory farmed beef eating corn in a shed thats never seen a blade of grass is whats actually causing the ghg seen in the reports.
We have already seen this narrarive been used to strongarm small farmers grazing cattle while the multinational farms get away with fucking the environment cos they can afford the cost of beurocracy.
We are all just 3 warm meals away from anarchy thats something we should do well to remember.
Ps. Its not "cow flatulence" its "enteric fermentation" (burps) cow farts just makes a better headline.