littlebabyjesus
one of Maxwell's demons
It doesn't show that really. It shows absolute emissions, so other large ruminants like buffalo are lower down simply because there are fewer of them. This study found that cattle and buffalo are pretty much the same regarding their conversion rate of food into methane, so you can view buffalo as equivalent to cows in this regard. Also applies to buffalo dairy farming, which is important in some parts of the world, such as India. (The amount of methane produced also varies a fair bit depending on the animals' diet and lifestyle, so not all cows are equal by any means.)Still shows that cows milk, pork and chicken are better for the environment than rice and buffalo is well down.
One thing that isn't explained in those graphics is how milk and meat have been separated out. Dairy cows are turned into beef when they are killed, as are their calves, as are dairy buffaloes and their calves.