Inspectors seized Whero's body for veterinary examination and necropsy.
A pathologist concluded the combination of starvation and suspected gastric ulceration and blood loss would have caused severe discomfort for Whero.
SPCA CEO Andrea Midgen said it is "unbelievable to think that a person would treat an animal like this".
"In the last weeks of Whero's life he was essentially a prisoner on a chain, at the total mercy of his owners and unable to move or get free for food.
"Why a person would treat their pet like this is beyond comprehension."
Munro, who claimed that she checked Whero's water every day, later admitted that she had noticed that he was getting skinny about two days before he died, but she did nothing about it.
She also said her ex-partner was responsible for feeding Whero and she did not feed or check on Whero herself because it was too cold in the morning before going to work, and it was dark in the evening when she got home.
Her ex-partner denied this.