I say almost, because there may be some subtle differences. But I don't believe they are enough to keep the tags separated.
For example, a screencast may contain audio narration. But I think desktop recording may have that as well.
Also, one can argue that a screencast should be a recording of the whole screen, while desktop recording doesn't need to be. But I can't find any definition of either word which says that.
Currently, screencast has 101 questions, while desktop-recording has 54.