I believe the harness is perfect for the smaller dog. If it's
fitted properly, you can lift the dog right off the ground with
it & not hurt the dog at all. Safety is always a concern with a
small dog or a puppy of any breed. MHMama, has Desi Lu
always rejected the harness or is this something new? Is the
harness smooth leather? If not, maybe it's scratchy to Desi Lu.
If you're sure it's not to small or otherwise uncomfortable on
her, then it's a matter giving treats for putting it on without too
much fuss. Good luck in training her.