Musically, "Hound Dog" says something about the connections and differences between R&B and rock & roll. Written and first recorded as a conventional blues song, it was converted into a rock and roll hit with some minor tweaking of rhythm and structure.
Willie Mae "Big Mama" Thornton's recording of "Hound Dog" reveals the song's blues origins. In live performances, she often introduced the song with a typical blues non-rhythmic call-and-response with the guitar before settling into the first verse. Once the song gets moving, the guitar, still in typical blues fashion, continues to answer Thornton with a fill after every line. During the extended guitar solo the roles are reversed—the guitar carries the melodic burden while Thornton provides a vocal fill at the end of each phrase.
In Elvis Presley's rock and roll rendition of "Hound Dog," the R&B influence is still apparent. The accent is still on the back beat and an electric guitar continues to provide the primary counter-point to the vocal melody. But the differences are apparent from the start. There is no blues introduction, the pace is more up-tempo, the rhythm guitar provides a more driving rhythmic frame for the vocals, a snare roll announces the transition from chorus to verse, and the bass line is typical of a hundred rock and roll songs of the era.