Payne inflicted a catalogue of non-accidental injuries on his pet including severe head trauma, a ruptured liver, a partial hip fracture and a prolapsed eyeball.
The vet who examined the post mortem report, said it was the worst he had ever read.
Payne was sent to prison for two years and nine months by Lancaster Crown Court and banned from keeping animals for 15 years.
RSPCA inspector Emma Dingley said it was the most shocking and violent act of deliberate cruelty towards an animal she had ever investigated in her eight-year career with the animal welfare charity.
Payne had denied causing unnecessary suffering to Rocko – whom he had brought from a childhood friend – claiming the injuries had been caused when he was performing CPR on the dog at his home.
The jury at Preston Crown Court took just 20 minutes to find him unanimously guilty of animal cruelty after a four-day trial last month.
Jurors heard that the RSPCA was contacted by a vet after Rocko was taken to them in February last year but was dead on arrival.
A post-mortem showed the puppy had suffered a ruptured liver, head trauma, a partial hip fracture and abrasions consistent with being scratched by fingernails, as well as cigarette burns to his groin area. There were also injuries to his abdomen and lacerations to his liver and he had inhaled the contents of his stomach.
In a statement read in court at the trial, inspector Dingley said: “The vet received the post mortem results back and immediately contacted the RSPCA. He told me on the phone it was the worst post mortem examination report he had ever read.”
A vet who also gave evidence in court said Rocko’s injuries suggested “intentional harm,” disputing the argument put forward by Payne’s legal team that the puppy had sustained his injuries as a result of Payne performing CPR after his pet had developed breathing difficulties.
The puppy had been seen at the vet three days before for his vaccinations and was reported to be bright, alert and responsive.
When interviewed under caution at a police station by inspector Dingley, Payne answered ‘no comment’ to all questions. Payne had been remanded in custody since the conclusion of the trial.
Inspector Dingley said: “I will never be able to comprehend what happened to Rocko and why such a young animal was treated in such a cruel way.
“This investigation will stay with me forever, but I’m pleased that we were able to get some justice for this little puppy, and I think the long custodial sentence reflects the gravity of this case.”