Somewhere a dog barked

I noticed the repetition of this sentence. First time, it appears on page 75: “...It was a flying saucer from Tralfamadore, navigating in both space and time...Somewhere a big dog barked.” I noticed that the sentence does not belong to the context very well. but I did not pay a big attention to it, because there are many moments throughout the book, when I was confused.

However, then I read the sentence second time on page 82: “...Somewhere a dog barked. With the help of fear and echoes and winter silences, that dog had a voice like a big bronze gong...:” Now, I stopped. This was the second time Vonnegut used this sentence and again, it does not belong very well into context.

            I do not know, what is the author trying to say with this sentence. I think, maybe he is trying to emphasize the silence of the moment. It was so quiet, that you could hear a dog barked somewhere.

What do you think about the importance of this sentence? Is it important at all?