Can the tumah water from after netilat yadayim affect animals if they were to drink it?
מים של נט"י שחרית אסור ליהנות מהם ולא ישפכם בבית ולא במקום שעוברים שם בני אדם:
Water which has been used for hand-washing before morning prayers should not be used afterwards for any other purpose. One should not pour it out in a house, nor any place where people pass by
mentions that the problem with giving it to an animal to drink is due to the fact that your gaining benefit from it. Seemingly, the Ruach Ra affecting the animal was not a concern
(כ) מהם - ע"כ לא יתנם לפני בהמת
From them - Therefore, one should not place them before his animal [to drink from].
When he discusses why not to pour it in a place where people pass by, he says because they can be harmed by the Ruach Ra.
Upon further research, I found that the Dirshu MB understands the issue with giving the water to an animal, that it will be affected by the Ruach Ra, not that it is an issue of having benefit. They quote the Derech Hachaim 1:5 that indicates as such (although in my humble opinion, it isn’t clear he’s referring to all 3 cases). They also refer to Biur Halacha 338:8 that mentions only the issue of Ruach Ra not assur to have benefit. (Also not entirely sure if this is a good proof)