Multiple realities
(covers information from several alternate timelines)
Milking was the act of relieving a cow or other milk-producing animal of its milk. A milking shed was one place where cows were milked. (VOY: "Spirit Folk")
In an alternate timeline 2373, Parell described her and other Klingon-affiliated Gaia inhabitants' lack of experience with agriculture, saying they'd neither plowed fields or milked chattel. (DS9: "Children of Time")