The animal welfare group said an inspector found a dead horse, a 32-year-old gelding named Pip, which belonged to Power.
"The Court found that Power recklessly ill-treated Pip with the result that he slowly starved to death and would have been in severe pain for months prior to his death," the SPCA said.
"According to expert evidence, Pip suffered from severe conditions that could have been easily prevented," said Bob Kerridge, SPCA Auckland Executive Director.
"He was found with ailments including dental, lung, nasal and stomach problems, which would have caused chronic pain that no animal should have to experience."
The SPCA said Power failed to check Pip from up close during the ten day period prior to his death.