Don't know if "Big Black Dog" by Emmylou Harris has been mentioned.

BIG BLACK DOG
As recorded by Emmylou Harris on "Hard Bargain" (2011)

A big black dog
A little too much gray around the muzzle
A big black dog
Why she ended up at the pound is a puzzle
A big black dog
Did she run away
Because somebody didn't treat her right?
Did they leave her out in the cold
Night after lonely night
A big black dog

A big black dog
I found her one day down there at the metro
A big black dog
Waitin' in a cage in line for the death row
Big black dog
Did somebody her put her out on the road
And did just not care?
Did they think an old dog was too much trouble
For them to bear?
A big black dog

Her name is Bella, Bella
You're not brown, you're not yella
Bella, Bella
My big black dog

Big black dogs, they're everywhere
Lookin' for a home, they're hungry and scared
All they need is food and attention
They'll give you back love,
Sometimes redemption I swear
You could find it there
In a big black dog

A big black dog
She may be a little rough around the edges
A big black dog
When you throw a ball, she'll always go and fetch it
This big black dog
With a brand new leash and a brand new collar
It's a brand new game
I love to see the way she runs to me when I holler
Out her name
My big black dog

Her name is Bella, Bella
You're not brown, you're not yella
Bella, Bella
My big black dog
My big black dog