"strong frame in front of a locomotive for removing obstructions such as stray cattle," 1838, from cow (n.) + catcher.
Entries linking to cow-catcher
cow n.
"female of a bovine animal," especially the domestic ox, Middle English cu, qu, kowh, from Old English cu "cow," from Proto-Germanic *kwon (source also of Old Frisian ku, Middle Dutch coe, Dutch koe, Old High German kuo, German Kuh, Old Norse kyr, Danish, Swedish ko), earlier *kwom, from PIE root *gwou- "ox, bull, cow."
Applied to the females of various large animals from late 14c. As an insulting or degrading word for a woman, 1690s.
catcher n.
"one who catches," in any sense, mid-14c., agent noun from catch (v.). Baseball sense is from 1867.