The non-related words for ox, cow and beef.
I can confirm the same at least in Czech, Ukrainian, Belarusian and Russian. But not in, say, Polish (where 'beef' has its root from 'ox')
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".
