Both the enteric methane production of dairy cows and emission of methane from manure should be considered
Out of the total methane emission of a dairy farm, about 58% comes directly from the cows, the remaining 45% results from farm operations. The 58% methane emission coming from dairy cows is split into 42% coming from enteric methane production and 16% coming from manure (see figure 1). This means that 72% of the methane emission that is directly related to cows is coming from enteric methane production and 28% is coming from manure.