Antinatalism is a "philosophical position that assigns a negative value to birth". Essentially, the basic premise is that suffering is bad and that creating a being that is capable of suffering is a negative thing. Additionally, deciding not to create new beings does not harm or deny anyone of anything, as theoretical or hypothetical beings do not exist.
Though antinatalism it is commonly used in reference to human procreation, it has direct implications for vegetarianism, veganism, and wild animal suffering.
Negative leaning utilitarianism is a type of utilitarianism that places a lot of moral weight on suffering, where acute suffering is very bad and there needs to be a lot of happiness to make up for it.
Farmed animals suffer. Would it be better if they did not exist?
At this very instance, there are billions of animals on farms experiencing stress, mutilations, and confinement. Additionally, there are countless numbers of chickens and other animals being killed in slaughterhouses.
Going vegetarian or vegan does not save any animals. Rather, it is a boycott that reduces demand for animal products which results in less sentient beings being born into suffering. With that, we can see the parallels to antinatalism and negative leaning utilitarianism quite distinctly.
If, hypothetically, we could snap our fingers and make all farmed animals disappear, I imagine most of us would do that as it would instantly result in a huge reduction of suffering. If you are on board with that idea, then you can see antinatalism is a relevant philosophy, at least when farmed animals are considered.
Wild animals suffer, too.
It's also quite likely that wild animals, especially insects which there is an incredibly large amount of, suffer quite a deal in nature.
Evolution does not select for happiness, but rather brute-forces its way to survival. Many animals thus reproduce in large numbers because only a fraction of their offspring will make it into mature adulthood. The ones that do not make it will meet a bad fate, suffering because of predation, parasitism, disease, or starvation.
If we, again hypothetically, could snap our fingers and make these animals disappear, would we? Should we? (This is not taking account environmental considerations, obviously.) Would it make sense for us to reduce suffering in such a way?
Say goodbye to farmed animal suffering, but maintain wild animal suffering?
If you say it doesn't make sense, how is that different from deciding to not snap our fingers for farmed animals?
Maybe you believe most wild animals lead better lives than farmed animals, which is a reasonable opinion to hold but might not be accurate.
Maybe you believe that if something is natural that it shouldn't concern us. However, if that's the case then that means we shouldn't intervene when diseases cause humans suffering, unless of course we are being speciesist and decide that humans are more worthy of protection for some reason.
The conclusion of antinatalism and negative leaning utilitarianism for humans is not very intuitive because we have strong evolutionary instincts to be optimistic as well as to reproduce. For farmed and wild animals, though, it might be easier to consider the possibility of its validity as an ethical philosophy.
Notes and Further reading.
One important note is that while antinatalism might make sense for farmed and wild animals, for humans it's actually the opposite as having kids can possibly reduce a lot of wild animal suffering.
Here is some further reading relating to wild animal suffering:
Longer and more in depth: