I would think the new owner, or whoever is caring for the horse at the time is responsible. Monty colicked a week after I bought him for £1. Thank god he survived, but even though it was no doubt caused by the horrendous state he was in, I didn't think about anyone being responsible for the costs but me.
If you are given a horse, it becomes your property and you are responsible for it's day to day costs, including vet bills and losses. I am sorry if you are the person it happened to.
id say new owner BUT..... you could say you have no recipt to prove purchase? so it could be said the horse is on permanent loan with no contract etc....?
tough one.
if it were me though and id taken it on id assume it were down to me.... but the above could be taken into consideration.
Any owner takes full responability as soon as the horse has changed hands.
If the horse was in poor condition than you are taking a risk anyway.
I took a very poor tb on years ago and paid 650 for her.stupid yes I know but needed to get her out that home. She was walking bones and only 5 yrs old. She had colic for 5 nights on the trot and vet said her system was never going to except food again and to put her day but I gave her 2 more days to pull through and she did. One hell off a vet bill but 5 years on iv got the most lovely horse and she trys her heart out for me. I would do it again but it's a risk you take