Animals not being able to jump up blocks when following you with wheat.

Put the summary of the bug you're having here

What I expected to happen was...:
Sheep be able to follow me as I have wheat in my hand

What actually happened was...:
Sheep jump but fail to actually jump up a bloc level

Steps to Reproduce:
1. get wheat
2. find sheep
3. get them to follow you up a block
4.profit?
http://i.imgur.com/ndT6xhP.png