The Cows shown in this photo are grazing on pasture in Marin County. This model of
feeding cows is becoming increasingly rare as diaries have shifted to a different type of
operation. Most of California's dairy cows no longer graze on pasture lands. Instead,
they are housed in concentrated feedlots where the feed is brought to the cows. This
can result in higher concentrations of manure being produced on smaller land areas
which can lead to more water pollution.