Question: I am looking at purchasing a horse whose tail has been blocked. Is there any chance that he will regain feeling in his tail over time?
Answer: A lot will depend on how and what his tail was blocked with and how skilled the person doing it was. Unfortunately there are many methods out there that are not reversible, despite what the seller may claim. In many cases the owner/seller may be unaware of the exact method used, and may have been told that it is reversible, so they tell you in all honesty that they believe it to be reversible. It may or may not be possible for the veterinarian doing a prepurchase to determine the exact way the tail was blocked, particularly if there are few marks/scars present.
Depending on your management situation it may be risky. The more a horse without tail function has to swat flies and deal with heat and humidity, the worse the problem. A horse stalled during the day in a dark barn with few flies will do much better. There can be other management issues and problems that arise with fecal material that collects under the tail, possible abscesses or other problems with treatment sites. Be cautious.