If a cat is born in the wild and ends up dying of a curable disease then it sucks for it but that's life. If you have a cat as a pet and when it gets sick you decide to abandon it to fend for itself and die in the wild then you're a bad person. Same outcome, very different ethical implications.
>So as long as you make sure to get your milk and meat from traditional farming
That's another gotcha that I really dislike. Every time the problem of animal suffering comes up there's always this opposition between "those crazy vegoons" vs. "the pop and mom farm who love their animals and take good care of them".
If that were the case, I agree that the situation would be very different. It's not though, you can't just ignore the woes of industrial farming when that's the vast majority of the meat products that surround us. These animals are for the most part born into horrible living conditions. In that sense I suppose that killing them early when they stop producing enough might be one of the least worse things that happens to them.
It would be like responding to somebody lamenting the deforestation of the Amazonia by bringing up the story of a poor farmer tending to his two acres of land in order to sustain his family. That's a best missing the point, at worse a truly disingenuous argument.