What if more pain directly correlated with better-tasting meat (or some other tangible advantage, like health benefits or medicinal properties)? I think you'd find many, many people who'd be okay with cows inflicted maximum pain for maximum yum meat, let alone meat that made them healthier than the alternative.
If there's a spectrum here, an instance of that spectrum exists for each individual too. Is it rational to believe we could ever agree on a single universal line on that spectrum for everyone?
Now I know you weren't referring to that.
As far as animal experimentation goes, it's pretty much illegal to do torturous experimentation on animals.
Getting IRB approval is difficult for anything besides normal life for an animal. Yes you can inject drugs into it etc., but pain to the animal plays a very large role in if you'll be allowed to do it.
* My wife is a cancer biologist who maintains and works with mouse models.
> If you replace the animals with humans (eating vs experiments) there is no question which one is more wrong.
Consent is the only issue here. What you're talking about isn't really ethics, more disgust.
If the meat I buy is from someone who mutilated the cow and optimized for maximum pain in the death of the cow then I would not buy that meat.
So there is a spectrum here. Just because we kill animals for food does not mean that it's ethical along the rest of the spectrum of harm.