The couple, were yesterday cleared of causing unnecessary suffering to their 13-year-old labrador Baron.
Last November they received two-year conditional discharges and were banned from keeping dogs for the same period after being found guilty at North Staffordshire Magistrates' Court.
Councillor Shotton, who sits on Stoke-on-Trent City Council and is a former deputy elected mayor, was forced to stand down from the authority's cabinet.
But yesterday judge Mark Eades, sitting with two magistrates at Stoke-on-Trent Crown Court, said evidence from veterinary pathologist Dr Udo Hetzel cast a new light on inferences from the first case.
Dr Hetzel, who carried out a post-mortem examination on Baron, said the dog had a heart condition and could have had a "sudden event" after the Shottons left him to go on holiday at 2pm on Saturday, July 15, 2006, and before the RSPCA inspector found him about eight hours later.
Judge Eades said: "Dr Hetzel said the factual accounts could all be true and the dog could have had a sudden event after 2pm. That could have been precipitated by heart problems and heart failure and therefore the inference the prosecution has been asking us to draw – that Mr and Mrs Shotton have been telling untruths – is not the case.
Dr Hetzel had also said the degree of suffering was not serious and would not reach the level of significance to amount to an offence.
"We are therefore formally of the view that when it comes to proof the prosecution cannot meet the required standard of proof."
"At the original trial they claimed that our much loved family pet Baron was emaciated and dehydrated. He was not."