also: ぼくじょうしゅ
noun
rancher; ranch owner
Refers to the owner or operator of a livestock ranch.
彼は広大な牧場主で、何百頭もの牛を飼っている。
He is a large-scale rancher who raises hundreds of cattle.
牧場主は毎朝早く起きて馬の世話をする。
The ranch owner gets up early every morning to take care of the horses.
牧場 means 'ranch' or 'pasture', while 牧場主 specifically refers to the person who owns or runs it.
Compound of 牧場 (ranch) and 主 (master/owner).