In the Needs tab, at the top next to Mood, is a toggle for the type of blood feed mode that you want your vampires to have.

so prisoner would be the humanoid non lethal right?

引用自 Meng：

so prisoner would be the humanoid non lethal right?

Under Needs, then top right of Vitae, click on Blood Feed Mode until it's Humanoid (Non-Lethal), then under it, click on the double arrows to switch to "Prisoners Only"

I prefer keeping a few legless prisoners along with a Nutrient Paste dispenses nearby helps, since you can harvest blood from them regularly, stopping the need to constantly micromanage your vampires blood levels, the only downside is that you need 5-10 legless prisoners to constantly harvest blood from, apart from that, I've had no major issues, in worst-case scenario, there's always wild-life creeping about.