Minecraft, what does it mean when your wolf has a orange collar?

Happened to me too, it does'nt mean anything

Assuming PC, as I don't know if it's different with other platforms;
The colour of the wolfs collar can change if you right click it with a dye in your hand.
In other words, you can make it whichever colour you want (out of the ones that have dyes).
So you probably just right clicked it with a dye in your hand.
Maybe.
Again, it might be different on consoles and such.

Its just the new default color of the collar(it used to be red). You can change it with dye like that other person said.