Minecraft wiki entry for Development_versions, associated text: Baby zombies now drop loot upon death.
Snow golems now attack silverfish.
Villagers now turn into zombie villagers when they are killed by a husk.
Now only adult cows can be milked.
Potatoes and beetroot can once again be used to feed and breed pigs.
Mobs killed by tamed mobs will now drop XP.
The Wither is no longer hostile to wither skeletons and strays.
Magma cubes no longer take damage from water.
Negative effects from splash potions no longer affect endermen (as they teleport away quickly).
Lured mobs no longer push the player around when they're riding a pig/horse/mule/donkey.
"Dye" button is displayed when trying to dye a sheep.
Untamed horses/mules/donkeys no longer follow the player when they're holding food.