Well as already pointed out most Vampires can feed off animals already. In fact it is the youngest vampires, the ones most likely to screw up that can all feed off animals.
All of which is fairly irrevelent. Even In OWoD where there was a unified world Vampire organization where younger vampires could feed on animals they never introduced this rule because it was unenforcabale. Any group trying to enforce such a unpopular banket ban would be overthrown overnight. Probably not violently but local Princes would simply remove their cities from the organization before they were removed themselves. In the cut throat world of Vampire politics making such a unpopular decision would be the equivalent of offering your opponents your throat and a knife.
This is before we even get into how exactly vampires would feed off animals. Most Vampires live in cities, where the overwhelmingly most common of prey is humans. Not to mention most vampires would have no idea exactly how to hunt animals and because they freak animals out are going to be lousy at it anyway.
Thats before we get in to the fact that the Ordo are not going to just hand over one of their greatest secrets when it is one of their advantages over the other groups.
Is animal blood still taste disgusting to Vampires in Requiem ?