My deontology module would complain if I spent money trying to get other people to sacrifice their own hedons for utilons, without being willing to do the same myself. It would complain so much that the guilt would feel worse than just eating unpleasant food all the time. And then with a vague goal of "probably donating enough to make up for eating meat" I would probably end up alieving that I had started eating meat just because I felt like it and the thing about saving money to donate was a rationalization, which would ruin my self-image as an altruist, and probably make me do less altruistic things in the future.
Givewell finds good charities for helping humans, but I think you can help a lot more animals per dollar, so if you are among the few who care about animals, you have a "comparative advantage" (stretching the meaning of term, I know, because it's not that others can't help animals with as small an opportunity cost as you, but that they won't) in helping animals. Low hanging fruit in improving animal lives have not been picked.
However, I'm not donating to animal-helping charities at the moment, because I think existential risk charity (actually, one existential risk charity in particular) has a higher impact.
But I still do occasionally argue with people I know in favor of vegetarianism. I've been somewhat successful. Of the people I have argued with in person for longer than an hour, one has agreed with me "eating meat is wrong," but said they would continue to do it anyway (and declined to watch the videos I suggested), one said they couldn't stop eating meat because they need it to continue being competitive at the athletics they do, but was pretty shaken (and also agreed "eating meat is wrong") (also declining the videos), one went from long-lapsed vegetarian to most-of-the-time-vegan, and one went from full omnivore to flexitarian, following my advice (based on these posts) to eat beef instead of chicken, eggs and fish. Edit: left out one, who as far as I know, is still eating meat and eggs unabated.
Do you think CEV / fAI will include concern for animals and things like not simulating or spreading wild animal suffering throughout the universe? If there remain doubts, then spreading memes for people to care more about animal suffering might be very important too!
I notice that a large fraction of Effective Altruism people are vegetarian. This makes sense: in general Effective Altruists take moral issues seriously, even when that means changing your lifestyle. I'm not sure it's a good balance, though.
One way to think about this is to convert it into money. How much would I need to be paid to give up eating meat? All animal products? How much money would I need to spend on myself to be about as happy as I would be with less money but continuing to eat animals? I'd probably be willing to go vegetarian for about $500/year, vegan for maybe $2000/year.
It turns out you can probably pay to convince other people to be vegetarian much more cheaply than that. I estimate the cost of a vegetarian-year at $4.29 to $536 while Brian Tomasik estimates $11 with better methodology (which I looked at). This is by placing ads on facebook for a site where people can watch an animial cruelty video and ideally become vegetarian or vegan.
If you would get more than $11/year worth of enjoyment out of continuing to eat meat, why not give $11/year to convince someone else to not eat meat for you? Or give $50/year and be on the safe side?
(While you're giving money, you should probably give it to the organization that you think will do the most good with it, which I think is probably one of GiveWell's top charities. The nice thing about money as opposed to actions is that it's easy to redirect.)
I also posted this on my blog.