I know (let's call him "a person that I know") who has in the past two months euthanized literally hundreds of large goats with The Blue Juice - and every one of them just had their heart stop beating in about 30 seconds. The only one that didn't work took two shots, most likely because the shot wasn't going into the vein properly. The knew it wasn't working because the heart just kept going, so the did a second shot.

All in all, it sounded very peaceful.

I would opt for that over a huge gun POP and fall... and potential missing - or blow back - or any other horror my brain can come up with. Just my personal preference.

Not my circus.  Not my monkeys.
      -Polish proverb