In general, I'm confused by the counter-factual ethics required to work this out. For example, if we stop eating meat and dairy, then we would have no incentive

In general, I'm confused by the counter-factual ethics required to work this out. For example, if we stop eating meat and dairy, then we would have no incentive to raise cattle. And without that incentive, cattle populations would drop dramatically; they would be limited to special preserves or zoos, or very marginal land. The species might not even survive. We don't have a stellar record of keeping large nuisance animals around if they have no economic value to us. It's not even clear (to me) that domestic cows are capable of surviving in the wild. So, in its most extreme form, the question posed is it more ethical to continue eating cattle and sustaining the species, or abstaining and letting the species go extinct? I don't know.