I don’t think this argument is sound. In your EV calculation you’re including the expected deaths over the thousand year period but excluding the expected lives over that same period. There’s an asymmetry in this comparison.
Also, I don’t see how x number deaths of a given species could be worse than the extinction of that species. The way I see it the first choice is save k lives over a thousand years, but the second choice is save k less lives over the same period and loose all future lives after that, forever.
The government should defend against the second case.
In your recent 80k podcast almost all the work referenced seems to be targeted at the US and EU (except the Farm animal welfare in Asia section).
What is the actual geographic target of the work that’s being funded?
Is there work being done/planed to look at animal welfare funding opportunities more globally?