A vet will intravenously administer an overdose of anaesthetic drugs into the horse’s neck. In some cases a sedative will also be given beforehand.
Shortly after the anaesthetic injection the horse will take some deep breaths and fall to the ground, where the vet will monitor the pulse until it has ceased. The heart will then stop but there may be some natural involuntary muscle twitching or leg movement.
The horse will tend to fall quite slowly and unpredictably but this can be controlled by an experienced handler. The vet may allow you to hold your horse’s head but some people find it extremely emotional so think carefully about who you want be there to support you.