*Cow card
This thing seems totally uesless... kinda funny, but useless.
Does it actually do anything or just for shits and giggles?

What? During the DRM quest, or the Gwent homage to it and the BDFI?

The latter is actually quite useful. Try it and see.

I was talking about the gwent card.

What else were you referring to?
And what's the gwent card do?

There is a sidequest in Skellige which is relevant.

Try the gwent cow card, (first round card). I corrected the acronym in your quote above, because I had a brain fart in the original reply.
It should make sense once you've tried it out.

forget it. I don't want to spoil it. Just play it in the first round, than wait for the second round.

What? A cow card in gwent? Where?! O_O

Part of the Hearts of Stone expansion.

I've finished it and I've never seen a such thing...

Screenshot pls.

Found it.
I have done all the sidequests in the Skellige islands, though... so I don't know when I can use it as you say... :'(

Right, so since no one else said what it actually does, I'll say it.

****spoilers of course*****












It works like the monster faction default power, in that it puts a monster on the field after the turn in which it was played, is over.
In other words, the cow is destroyed and replaced with a random monster form your monster deck.
Neat little addon; not really worth using at end of the game, like most things from the expansion.

Not my saying. I have no idea which Skellige side quest Lieste is referring too. Only ones I can think of are the Gwent quests.

Yeah sorry, I've just quoted you for the first part of my answer, the second part was generic