Unfortunately don't have OP; if I did, I would've just done /kill @e[type=cow].
As for mods, should I use Forge, Fabric, or Quilt?
Use fabric, forge is too slow.
Last time I did /kill I couldn't checkmate the dead cow, so I don't recommend messing with that. Maybe you could with a few teleport commands but meh.
Depends on version, but Forge works fine. Maybe 1.12 draconic evolution, make your queen a chaos dragon and go to town. Just make sure they don't know the mod, it'll take months before they're able to mate you.
ThatOneKirbyMain2568@kbin.social to 
Unfortunately don't have OP; if I did, I would've just done /kill @e[type=cow].
As for mods, should I use Forge, Fabric, or Quilt?
Use fabric, forge is too slow.
Last time I did /kill I couldn't checkmate the dead cow, so I don't recommend messing with that. Maybe you could with a few teleport commands but meh.
Depends on version, but Forge works fine. Maybe 1.12 draconic evolution, make your queen a chaos dragon and go to town. Just make sure they don't know the mod, it'll take months before they're able to mate you.