Ok so I am a werewolf and I was able to feed to regain beast time in the tutorial/attack the silver hand dungeon.
After doing some normal quests I decided to have some fun so I transformed and attacked some cows but I could not feed on them?
I then thought maybe you can only feed on humans do I tried that but I still could not and eventually my health got too low and I was killed?

Also its nice to see a post from Bethesda today but its not very informative, we know you are working on a new patch but what we dont know is when it is due, (exact date/rough date?)