Horses, Donkeys, Mules, Zombie Horse and Skeleton Horse Never Drop 3 Experience

Horses, donkeys, mules, zombie horse or skeleton horse only drop 1 or 2 and never 3 experience when killed by me and a tamed wolf, they should drop 1-3 experience.

According to the official Minecraft Wiki: "Horses drop 3 experience when killed by a player or tamed wolf."
http://minecraft.gamepedia.com/Horse#Drops