Significant Change - Dogs Coat

Question
Our dog, Maisy, will be (3) years old in October. She has recently shed "massive" amounts of fur.  Her coat used to be VERY soft and shiny; now it is rather "coarse". [I prefer her this way; she looks more "svelte"/athletic and less "rotund"!]  My wife is worried that there is someting wrong with Maisy.  Our vet, frankly, has given very little guidance. He simply says "this is not unusual".  That may be true, but we would like to know more. Here are some facts which may be of help to you.  

1) Maisy is a mixed breed - largely chocolate lab and spaniel (Brittany?) We rescued her from the local pound.
2) She has lost NO weight during this extreme shedding process.
3) This is the ONLY time she has shed this much fur.
4) Her diet has not changed.
5) Her demeanor/energy/etc. has not changed.
6) Since this "radical" change in her coat, she is shedding very little now (yay!)

T H A N K S in advance for your help.  Best wishes, Mark and Anne Michener, Dubuque, IA

Answer
While some shedding is normal, excessive amounts can indicate problems in the skin.  There are some hormone problems that can result in hair loss.  Ask your vet if your dog might be hypothyroid.  That is a common reason for excessive hair loss in dogs.