Loaner put my horse to sleep?

My mare has been out on full loan for the past 2 years. She suffered an episode of colic and the loaner had her put to sleep without my consent. By the time I arrived she was already gone. I don't disagree with the decision but I just wish I could have been more involved and had some warning so I could say my goodbyes. I was just wondering what the legalities of this actually are? Was this legal from her side and the vets? I have no intention to pursue this as the loaner gave her such a fantastic home and loved her to bits, I think I just want something to be angry about.