I'm seeing this as well on 14w32a. If I hold wheat, cows look at me as if they want to follow, but they don't move, or move very slowly. I basically have to push them across water.
I'm also seeing this behavior in 14w31a, with cows and sheep. My work around is to use slabs to make steps that they can climb.
Bah. I tried to search for this, but the title didn't match because I put a space in 'nether portal'. Ah well. Sorry about the dupe.