Can't help you with sources but, if it interests you, you may like to consider building this theory in:
Figures suggest that (due to the massive amounts of land needed to grow food/pasture/house/process/store livestock) an omni society needs around ten times more land to sustain itself than a vegetarian society would.
Basicaly a vegetarian society needs 90% less land than an omni society.
From memory the touted figure is that 30% of the entire land surface is used for agriculture. Allowing for deserts, mountainsand other unusable land areas that 30% may be 50% or more, of all the total useable land surface on the planet.
By those figures meat makes land scarce and whatever is scarce soars in value. Not just agricultural land but ALL land. Housing, commercial the whole shebang and caboodle
That is massive reason for the land owning classes to do whatever is necesary to make meat affordable by subsidies.
Wouldn't be so if it wwere not the fact that the dimwits who eat meat are the ones actualy paying (through taxes) for the subsidies anyway.