Actually, bovines are smarter than horses. So are pigs. But the horse is cuter, no doubt, and the taboo on eating horse meat has nothing to do with food sanitation & everything to do with not eating My Little Pony.
I would beg to differ. I spent many summers in my youth on the family dairy farm. We had both cows and horses and I have yet to meet a smart cow. However I have worked with many smart horses.
A cow eats, poops and farts and refuses to be trained to do anything except stall and accept milkers.
A horse, on the other hand, can be trained to do tricks and respond to verbal commands ... try that with a cow.