Multiple realities(covers information from several alternate timelines)
A cow is an Earth mammal used in agriculture, primarily for its milk. Cows are also rasied to be slaughtered and eaten. Cows are ungulates.
In an alternate reality version of 2255, a figurine of a cow could be seen in the Shipyard Bar. (Star Trek)
The Bringloidi colonists brought a cow aboard the USS Enterprise-D in 2365. This cow was the descendant of twenty cows carried aboard the colony ship SS Mariposa. (TNG: "Up The Long Ladder")
In 2376, Tom Paris turned Harry Kim's holodeck date, Maggie O'Halloran, into a cow as a prank, unknowingly causing the people of the Fair Haven holoprogram to believe that Paris and Kim were evil spirits. (VOY: "Spirit Folk")
Cows were used to make hamburger meat and other types of beef. (ENT: "Carpenter Street"; VOY: "Fury")