cruelty_cow = IntModifier * Animal_Intelligence /(AmountOfProvidedMeat/Deaths) * FrequencyOfEatingThisAnimal
Solve for:
Min (cruelty_cow + cruelty_pig + cruelty_octopus + ...)
Where AmountOfProvidedMeat > NeededMeatForHealthyDiet
And Cost * AmountOfProvidedMeat < Food_Budget
I've generally found that maximizing on Fish, Chicken, and Cow (in that order) seems to be the best bet. I tend not to touch veal, lamb, or octopus.
If you refuse to eat even humane veal (free to roam and milk-fed), then IMO you should refuse dairy entirely.
It might also be worth considering that the entire concept of humane dairy is questionable. It depends on separating mothers from calves, and either eating the latter or weaning them at far too young an age, or both. Cows are dumb, but they're not that dumb, and more importantly they are prey mammals with strong "familial" instincts. The process is fundamentally at least somewhat cruel.
The human body is an amazing thing that is simultaneously a fucking pain in the ass. There is no "one truth" for food.