In russian (and most likely some other slavic langauges) beef ("говядина") is meat of any cattle because it comes from anchient-russian "говядо" which literally means "cattle".

Pretty much same for ox - from the old form of "big" "великий" - big animal.

Cow "корова" most likely comes from protoslavic korva and most likely inherited from ancient-indian "carvati" - "chewing".