Apparently, horse punching (known as horse breaking) was common enough in Vienna that they started making statues of the occurence.
This post on Swords and Dorkery puts forward a possible origin for the infamous camel slugging scene in Conan the Barbarian. As you're all no doubt sick of hearing, I really don't like that scene for many reasons, but the idea of there being a historical context intrigues me nonetheless. After all, there are plenty of historical references and allusions in Conan the Barbarian, perhaps there's something to it.
Well, apart from Blazing Saddles.
Calling a halt, [the Byzantine Catapan] sent a messenger across to them, offering the choice: either they could leave Byzantine territory peaceably and at once, or they must face his own army in battle on the morrow.
The Normans had heard communications of that sort before, and knew how to deal with them. During the harangue one of the twelve chiefs, Hugh Tuboeuf, had approached the messenger’s horse, and had been stroking it approvingly; now, as the man finished, he suddenly turned and struck it one mighty blow between the eyes with his bare fist, laying the luckless animal unconscious on the ground. At this, according to Malaterra, the messenger in a paroxysm of fear fainted dead away, but the Normans, having with some difficulty restored him to his senses, gave him a new horse, better than the first, on which they sent him back to the Catapan with the message that they were ready.
After a little digging, this anecdote appears to corroborate with a similar passage in Jim Bradley's The Routledge Companion to Medieval Warfare.
VENOSA, BATTLE OF, 17 MARCH 1041
In 1041 the Lombard, Arduin, established Norman knights at Melfi in southern Italy. Within days they captured Venosa. That zv1 54 year three battles were fought and won against the Byzantines, the first near Venosa at the confluence of the Olivento and Ofanto. The Byzantines, under Catapan Doceanus, challenged the Normans to fight or leave. When the messenger had finished, the Norman Hugh Tuboeuf punched his unfortunate horse between the eyes, felling it. The rider fainted and was sent back on a new horse with the reply. The battle was fought next day. Many Greeks and Varangian Guards were killed, some drowning in the river. The Byzantines withdrew.
- The Routledge Companion to Medieval Warfare, page 162
The mighty Hugh Tuboeuf even has his own page on Wikipedia:
Hugh Tubœuf or Tudebusis (French: Hugues Tubœuf, Italian: Ugo Tutabovi) was a Norman adventurer who went to Southern Italy around 1030 in search of glory and riches.
Hugh took part in the Sicilian expedition of George Maniaches in 1038. He was one of the twelve leaders of the mercenaries of Guaimar IV of Salerno who elected William Iron Arm as count at Melfi in September 1042 and received a twelfth of the conquered territory: the barony of Monopoli.
Tubœuf is famous for an event which took place on the eve of the Battle of Venosa in 1043. After receiving the envoys of the Byzantine catepan of Italy, Argyrus, himself a Lombard turncoat who had abandoned the cause of the Lombards and their Norman troops, with offers of peace, Hugh began patting the horse of the chief ambassador on the neck and then punched it with such force as to knock it unconscious. The envoys were sent back with news of the terrible physical strength of their adversaries. The battle went to the Normans.
The date of Hugh's death is unknown.
Jeez, that's Cormac Fitzgeoffrey level strength there, taking out a horse with a strong jab. I still don't condone wanton acts of animal cruelty, but good grief. I wish there was more information about this fascinating character on the 'Net, but I can't seem to find anything. I did find out about some other awesome Normans like William Iron Arm, and got reacquainted with the Norman Conquest of Sicily, but I can't find much else. Sadly, I doubt Hugh could've met Cormac, since his heyday was a good half-century before Cormac was born. Cormac's father, Geoffrey the Bastard, on the other hand...
Still, even given the awesome Hugh Tubœuf, this is the only thing that will ever come to mind when it comes to Conan punching animals: