Ever since the latest update, in addition to no slimes spawning in swamps any more, cows and horses have stopped spawning in my Survival Normal realm. I've searched in a 500 block radius, through a variety of biomes, around my base over the course of a few days, and have only managed to find one cow and a previously saddled horse that someone lost. And I haven't seen many pigs, either. Sheep and chickens are not plentiful, but still present.