From 8-Track Heaven:
About 6 months ago I received a series of e-mails from a gentleman in Italy who claimed to have developed an 8-track system for use on his horse! Well, he eventually sent photos to prove his claim, along with some technical data on how it all works. Check it out!
More about the system at the above link; no word on how he trained the horse to be cool about riding “through small towns and countryside with Lynyrd Skynyrd, Boston, Christie and other similar cool tapes playing loud”.
Bridlepath 
[…] According to this post on the Bridlepath, this fellow and his horse, both equipped with long. luxuriant manes, are big fans of Seventies music. On their treks through the Italian countryside, they could not be without their precious tunes. […]
[…] The amazing Horse-o-Phonic! […]