I have been using HerbaDry to dry feed my cows for over 6 years.
The benefit to me is that I never use antibiotic dryers again and thus reduce the overall antibiotic use on my farm. Two days before the cows are dry, I give them straw as much as they want and about 2 kg of corn so that milk production goes down well.
I give that for 8 days and at the last milking they get a dose of HerbaDry.
Then they get a drying ration: 12-13 kg corn, lots of straw and 100 gr Herbamin Dry.
If I have a problem with a cow with a high somatic cell count, I combine it with Herbamas one week before calving (2 doses with 1 day in between).
This results in a decrease in somatic cell count and no mastitis at calving.