Sam, Ben,
Re: Rabbi Schachter’s issue. I wasn’t aware he held that. You both say he mixes meat (and would eat say hot dogs) because we check for the miut hamatzui, but I’m not sure why only a miut hamatzui is a problem, and not any rov. Is there some sort of rov in the gemara that even 1/60 cows don’t have any of the other treifos?
But the real issue I was driving at is: Does the gemara say that R’ Yehuda held you can’t mix milk? no. Does it say that we are allowed to because it is less than 1/60? no. It kind of seems like DY’s answer is correct.
And as far as that the cows are known in the dairy which one has stapled stomach, can we discuss that a bit?
The rov of rov beheimos used is a ruba d’leisah kaman, so we aren’t using the lomdus of kol d’parish, rather, the rov is paskening that there is no treifah at all. But if you call up the dairy, you can easily determine that in fact some of them are treifos. So then we’d need your ruba d’isah kaman of kol d’parish (is this kavua?), but, like you say you can’t have a rov there because you know which are which–you can only have a rov once it is parish but by then it is all mixed together. yah, that sounds pretty bad.
But that problem is only for non-CY which has stapled stomachs because then we know some are treif and need the ruba d’isah kaman. But for CY, we can just use the ruba d’leisah kaman, no?