First, for the style, it's not bad. There's plenty to be argued regarding the methods and particulars, but you are still developing and "cultivating" your own style, so don't sweat that just yet...
As to the content, actually, there's a miserably tiny percentage of the "out-gassing" from cattle (or any other flatulence for the matter) that accounts for methane. Yet, satellites have noted sizeable emissions from natural termite mounds through Africa and Australia... But of course, we can't blame anything natural if we (our government) have a chance at fines and taxes on the ranchers for their cattle raising and (evil) ways... I wouldn't point out such a contradictory point except that you have to be careful as an artist seeking publication that you put out GOOD information. (and by all means, I'm interested in the possibility of being wrong)
It's dangerous to blindly jump on a band-wagon of inertia and destroy peoples' livelihoods when you don't actually have all the data at hand... That's just a cautionary point...
As to the animation, nicely done... fluid and workable... easily understandable, and the voices and sound FX sync' up pretty well. I would (again) be cautious about the points I brought to view for pulication, because if you put all the farmers and ranchers out of business with this thing, what are you planning to eat???
AND what are you going to tell your darling (AND STARVING) grand children when you've accomplished your mission against the evils of farming and ranching herbivorous animals???
Good Luck!