Don't load Mip 0 for certain textures based on a condition?

Hello! Ok so my goal is to reduce memory sent to the GPU by marking a texture with something like "Don't load Mip0 if *condition*". So what I'm trying to achieve is basically something like a **QualitySettings.masterTextureLimit**-setting but on a per-texture basis. Consider that I'd like to (on some devices) not use the full resolution texture on cows, but I do on chickens. Does anyone have any pointers as to how I could achieve this? Cheers!