How can anyone approve this. I mean I understand we test medication on animals with the goal of helping thousands or more people. But this is just unethical and indefensible.
There are a lot of things that would be "pretty cool" as long as we don't worry about the suffering they inflict. I mean, in a sense, factory farms are pretty cool in their level of technical sophistication and efficiency of converting grain and energy into meat. The accomplishments of breeding to generate chickens with breasts so large they can't stand up or procreate without intervention, and grow so fast their skeletons can't keep up with their weight are amazing. The density of animals we can grow while keeping loses to disease acceptably low with antibiotics is also remarkable.
And yet, all of these things that are "pretty cool" are also horrendous on a scale that is difficult to comprehend. Raising an intelligent animal like a pig just to harvest its heart for a human might be an ethical trade-off you're comfortable with - and given our treatment of animals for food I've no doubt that it's one society at large is fine with. If my own parent needed a heart transplant, I would likely have a hard time saying no if this were available. But from a Rawlsian perspective, thinking in advance, I don't think this is something we should be doing.
You know, it would also be pretty cool to have some kind of animal that could perform human-level tasks and ideally could understand human language. Maybe we could distinguish them from people based on some superficial physical characteristic like skin color 🤔