doggone (verb) is an expression used as a more polite form of damn
Definition from Merriam-Webster (http://www.merriam-webster.com/dictionary/doggone)
From Beloved by Toni Morrison ( page 94)
Sleeping with the sun in your face is the best old feeling. Two times I did it. Once when I was little. Didn’t nobody bother me then. Next time, in back of the wagon, it happened again and doggone if the chickens didn’t get loose.
Amy talks about taking a nap and how it feels. she says sleeping under the sun is the best feeling and she did it twice – once when she was young and the other time in the wagon. She says doggone if the chickens didn’t get loose in the back of the wagon she would have been able to sleep more under the sun.