I’ve been present for 3 horses to be euthanized, 1 was mine, 2 were friends horses done by different vets. None were sedated before. I asked about sedating first and both vets said that when you sedate an animal before you inject the euthanasia liquid, the animal can take up to 4 or 5 times longer to actually die.
The traumatic part is watching the horse fall when just the euthanasia is injected, but both vets would try to guide the head so that when the horse went down, they wouldn’t let their head hit the ground hard. That was a kindness to the horse, but mostly for the human as it’s already traumatic to put your horse down to begin with.
This is the timeline that my vet told me, to the best of my memory.
• Once the horse has been injected with the 2nd vile, they’ll take a couple big breaths as the brain starts to go unconscious. They’ll lean backwards and fall to the side…hitting the ground about 4 seconds after the 2nd vile is injected and be totally unconscious.
• Once on the ground, the brain is unconscious, but will fire nerves to the limbs, sometimes they’ll kick or twitch a little (none of the 3 I watched did this, maybe one leg moved, but otherwise they were still)
• The brain stops sending signals to the lungs to breathe, and the heart will stop beating within about 2 to 3 minutes.
•Total brain death occurs 3 to 4 minutes after injection. You touch the eye to see if you get a blink response. If no blink response occurs (which is involuntary in all animals) the brain is dead.
All three horses were dead within about 5 minutes (as in no reflex when you touch the eye)
I suppose the only way to ensure instant lights out would be to shoot the horse in the brain. It’s more traumatic for the human, but for the horse, it’s an instant light switch.
My vet (who is sound of mind) told me that vets have the highest rate of suicide out of most professions, and if she were to go that route, doing the euthanasia you give horses would be the choice to make. On a human you’d be unconscious in seconds and dead in about a minute.
I would say the quicker the death, the more kind you are being. I wouldn’t want my horse to be laying, sedated on the ground for 30 minutes while the euthanasia takes longer because the heart rate and breathing is already slowed down.