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")
Admiral Milius briefly went AWOL due to the fact that he was frustrated that he never received any exciting assignments but was rather relegated to milking space whales. (LD: "The Best Exotic Nanite Hotel")