Gaja, yes.
Only about 6% of Quebec is agricultural land, and only 3-4% can grow crops. The rest can grow hay and pasture, trees, and tundra. Ontario is better because of the region from Toronto south-west to Niagara, but still most of it is not suitable for agriculture.
In my region bio-gas is as likely to be a product of swine production because of confinement housing (also capture from old landfills) and manure lagoons. Pigs can live on pasture a good chunk of the year even here, but the breeds that do well on pasture do not do well in confinement, and the breeds that do well in confinement don't do well at all on pasture. To get pigs on pasture will be a more radical shift than to get cattle on pasture/hay. Someone in Vermont has totally pastured pigs, and Vermont has pretty tough winters. But the breed is a heritage breed, the modern breeds just can't cope. Again, our chickens won't go outside much in winter, but the layers don't have to be raised and housed in cages. We have undergone such a radical shift in our meat production techniques, and most people have no idea. Crops too.
Re cattle and fats, what people don't realize is that cows do not digest cellulose, although they eat a lot of it. The bacteria and protozoa in the rumen digest cellulose, and produce basically short-chain fatty acids. What the cow's digestive stomach digests is dead bacteria and protozoa and the short-chain fatty acids. So yes, they do digest some fats very nicely. This requires an alkaline rumen. When they are fed grains the rumen is not as active, the rumen shifts to being less alkaline, and not only do they produce more methane, but they also are more prone to have acid-resistant E. coli, which is where some of our E. coli outbreaks come from. All ruminants do this magic of cellulose into meat, which is why they are such common domestic animals, in so many diverse climates. They are much easier to feed than a horse.