I have no faith in a regulatory framework being enacted and enforce which will minimize this suffering while keeping businesses profitable.
So it becomes a math game. Either this cow produces the 700lbs of meat in a normal lifetime or with lab meat it produces n tons of meat (depending on how much meat can be produced per sample).
Who knows, maybe this ends up with a few cows living long lives since it's not their meat that matters but rather the quality of the stem cells they produce. But I'm guessing it's more likely these stem cells first get extracted from animals either already butchered or destine for the butcher.
Note that we are talking about the growth medium here, which is used to grow the stem cells into the final product. So it should be the quality—or much rather the quantity—of the extracted serum from the animal (specifically the animal’s fetus or womb).
The technique is called a "biopsy" and while it does hurt, the animals recover pretty quickly from it. Branding is far more painful.