Pick the (horse) meat out of this one:
Race Horse Death Watch
It's not just Aintree or the National, it happens all the time all over the country, just we don't usually get to hear about it. Sadly but inevitably if a horse is badly injured in a fall treatment and recovery are often impossible and at least the horse is humanely disposed of swiftly.
I'm afraid it's part of the sport, and short of banning a major sporting industry and leisure pursuit it will continue, unpleasant as it may be.
After all we haven't got round to banning boxing yet and that can have equally serious consequences, but for humans.
However much you may dislike it, fox hunting, the one activity that has been banned, at least had the serious and necessary purpose of reducing the fox population among all the other criticisms that have been levelled at it. It did this at least as effectively as any methods that have had to be used since the ban.