Put your operating system (Windows 7, Windows XP, OSX) and Java version if you know it here
I tryed 1.6.1 and i maked a horse tame.
then i lead the horse into a boxer and the horse bugged into the wall and died...
The horse just walked into the wall and died after 5 seconds.
Steps to Reproduce:
1. lead the horse into a boxer
2. it will walk into the wall
3. the horse will die