Carlotta Ferrari wrote many organ pieces, all of them available on IMSLP.
This Pastorale has imho a haunting character.
On the one hand there is joy, because of the newborn child, but on the other hand the pastorale foresees the pain and sorrow this child will have to pass through as the child of God, bringing God's words to earth.
Well, just my two cents ofcourse.
Can be that Carlotta had quite different ideas when writing this piece, but that's how it sounded to me.