Cows no longer shows Harts when feeded

Put the summary of the bug you're having here

What I expected to happen was...:
Cows normaly shows harts when feeded

What actually happened was...:
Cows no longer shows Harts when feeded

Steps to Reproduce:
1. I just feed the Cows.
2. Restrarted the Game
3. Feed the Cows again (Still no Harts) However they are producing baby Cows.