You can't raise livestock for hundreds of millions of people "ethically" -whatever that means-. That's why people industrialized the process, and on most big factories there's little human intervention.
I can't picture the day where people stop eating meat. It just won't happen, not matter what arguments you present.
The best way to go is replacing it, and the perfect postulate is lab meat, which I hope, is going to be massively produced at low cost in the next ten years. And even if it doesn't ill people, tastes the same as natural meat, you will find resistence.
So, to summarise: lab meat at lower cost than natural meat, demands plunge, billions of animals are saved every year.
once lab meat/lab milk can be produced at or below cost of farming, cows will likely go extinct, unfortunately.
A less vulgar correlary is that once horse racing is outlawed, horses will mostly go extinct as well, as the racing industry is responsible for being able to acquire feed/hay/veternary care for the average horse owner. Without it will be practically impossible to keep 'pleasure' horses.
From what I've heard most land-use in the world goes towards animal agriculture - mainly for growing feed. Don't quote me, but I think it's over 40% of all land use in the USA. On balance I'd be far more concerned about the destruction of habitat for already endangered wildlife.
I can't picture the day where people stop eating meat. It just won't happen, not matter what arguments you present.
The best way to go is replacing it, and the perfect postulate is lab meat, which I hope, is going to be massively produced at low cost in the next ten years. And even if it doesn't ill people, tastes the same as natural meat, you will find resistence.
So, to summarise: lab meat at lower cost than natural meat, demands plunge, billions of animals are saved every year.