To add on - the feed we give cattle exacerbates methane production in their gut.
Cattle fed high-grain, low-forage diets produce 42% more methane than those fed-low grain, high-forage diets (Boadi et al.,2004). Methane (CH4) is composed of carbon and hydrogen. The formulation of diet influences the carbon: nitrogen ratio of manure, which impacts the amount of methane released. Diets high in grain have higher levels of readily fermentable carbohydrates, which create methane to be released into the atmosphere. Grain type can also change the amount of methane emissions. During the finishing phase, cows fed a corn-based diet released less methane than cows fed a barley-based diet (Beauchemin and McGinn, 2005).
So there is nothing “natural” about the excess methane produced by cattle because if they were naturally foraging the amount produced is lower.
Yeah, cows are adapted to eat grass, but that doesn’t fatten them up. So we give them corn and whatnot instead. It’s a generally unhealthy diet for them. As in, they are literally more prone to disease because a grain diet impacts their immune system.
When you offer a cow grass in one hand and grain in the other, they will always go for the grass.