Similar situation for me just a few days ago. Riding on the Sparta-Elroy Trail, coming “down” from the 3rd tunnel doing 17-18 mph, spotted a doe and her fawn about 25 yards ahead of me. I shouted out to get their attention and the fawn bolted right while the doe went to the left. I immediately slowed down in the event that the doe decided to follow her fawn. Fortunately, neither came back to the trail. Looking back, don’t know if it’s best to maintain speed or to slow down? Kind of a crap shoot I guess.