Bovaer in dairy cattle feed. What do we know?

I've tried to find out more about this on and off all this week.

As we only buy organic milk (and it's not used in the feed of those cows) in some ways I'm out of this food loop. However, I am concerned about health of both people and animals down the line... and many of the big supermarkets are buying from Arla so the milk from the trial is presumably just being bundled in with the rest.

Do we have scientists on here that have been watching the science of this please?