The population of livestock is artificially high because of meat industries. Additionally, all animals in a meat producing farm will be killed already. That's the entire purpose. Simply slowing the reproductive rate of the industry would reduce the populations on a fairly short timeline. I'm a meat eater myself, but using the killing of animals as an argument AGAINST slowing meat production is not very logical.

Which would you prefer? A thousand people living freely or a hundred thousand people living in cages too small to stand up in?

Get outta here with pretending that big number = better. Those animals are raised in horrifying conditions explictly to be slaughtered. They wouldn't exist in the first place except for the cruelty and greed of the meat industry. We routinely acknowledge that there are 'fates worse than death' for people, but when it comes to animals people seem to forget that. With the ending of the meat industry, fewer animals would exist, but they would be much better cared for.

Meat eaters are already decimating populations, they are Thanos with a universe conveyor belt, clicking every second.