Cattle contribute to methane gasses through their burps and farts, as well as their shit fermentation ponds and maybe other things im forgetting.

Cattle, like cows, deer, sheep, and buffalo, belong to a specific group of animals known as ruminants. Characterized by their four-chambered organs, ruminants are able to rapidly have a large meal of grass and hay and later digest it by re-chewing it in their mouth. In the cattle’s stomach, a rumen microbe called methanogen converts the excess hydrogen and CO2 produced during the digestion of this high-fiber food to methane. This methane, called enteric methane, is expelled from the cattle’s body as belching or burping.

In 2022, methane from enteric fermentation accounted for 27.4% of total anthropogenic [caused by humans] methane emissions in the US and 3% of total gross emissions.

Source (links the EPA report these numbers come from)

There have been other studies on this topic I’ve read in the past but that was just first one that i came across