Not a problem. It's actually 2 acres of pasture that they're on. I'm able to graze them the same amount of time that anyone in Oregon with 10--20 acres can during the spring and summer when the grass is fast growing. Most of of the time I'm mowing the pasture be cause 2 cows can't keep up with the growing grass.
Again, I can't narrow down the client base like that, mainly because we're almost an hour outside of Portland and it's everything I can do to market my product to get people to make the drive. Even the herd-share drop off I do closer to town is a more a drive for some. I get your analogy with "year round corn" but it's true that what you're doing with the winter lay off is not something found in traditional dairies, or farms. People always were able to extend milking through winter, and for thousands of years it didn't seem to be a problem for them, or the cows. So my question is, who's example are you following? Or are you using the seasons as a guide?
According to the "AI guy," who does all the dairy cows in this part of Oregon, some of the heritage breeds are trickier than Jerseys and Holsteins. And Guernseys (I'm phasing out of that breed now because of this) are notorious for not getting bred. My cows are very easy to detect when in heat and I've had him come out early in the heat, late in it, back to back, multiple samples going in at once, etc.. And currently I have one cow that's he's been inseminating for 8 consecutive cycles. Now how is that going to fit into a seasonally in tuned milking schedule? It's not. This very question came up at a series of raw-milk workshops at a micro-dairy here in Oregon given by Tim Wightman
http://www.realmilk.com/bios/tim-wightman/ . When asked about trying to coordinate the breeding in order to calve in the spring, Tim said that you "breed cows, when you can breed them." Basically there's such amount of uncertainty with getting the pregnancy to take, that people have found that it's best to get the cow pregnant when the opportunity arises. And if we look at history, it seems people who had dairy cows thought the same thing.