No.. think of a jersey. 800lb cow that milks 80lbs a day. very high milk #s, very low growth #s. You want to inject the growth with the sire. There is no point in feeding 1500lb cows. Ideally, I would have 1000lb cows that are heavy milkers and when crossed with a high growth bull, the resulting calves would get the growth genetics from their sire and the fuel to grow from their mothers. This is the situation where you look out and see calves suckin on their momas that are taller than they are. When you start seeing animals that are high ww and high milk, be learly. While the ones with high ww may also milk more than average- I guarantee you its not more relative to their mature size. Many of these type animals are highly inefficient in their conversions of grass/feed to lbs of gain or lbs of milk production. Think dual purpose. They do both but lack the specialization in either.
The only reason people generally shy away from high milk numbers is that high milk numbers are generally associated with harder doing cattle because the majority of those heavy milkers are jus big ass cattle. Find the ones that aren't. They do exist. Perfect example is the shorthorns that J Bar J has in Fallon Nevada http://joycebarnes.vpweb.com/Ranch-Cattle.html
While JbarJ refers to them as "milking shorthorn", they are not the type that most associate with milking cattle... or milking shorthorns for that matter. They are 1000lb cows that milk heavily and because of their reduced mature weight, they have the ability to milk heavily without falling apart in the pasture. You put this "TYPE", notice I didn't say breed as Im sure there are animals of this TYPE in many breeds, of cows with a terminal continental sire and you'll be sailing down the Tahlequah singing Kanye's "La,la,la,la wait till I get my money right" $$$$$$$$$$$$$
Be fearful when others are greedy and greedy when others are fearful.