Subject: what is the average heart rate of a dog (labrador retriever)?

I have a black labrador, and i was laying on his chest like i usually do.  
I noticed that i couldn't really hear his heart beat; therefore, I was 
wondering what the average is, so when i get my mothers stethescope i can 
make sure that his heart rate is ok.  He is 12 yrs old, and of course, i, 
being the usual concerned pet owner, was wondering if his heart is still 
working under normal conditions for a dog of his age.

Re: what is the average heart rate of a dog (labrador retriever)?