Kevin Paton from the RSPCA described Ben's case as "the worst case of obesity" he had seen in a dog in 35 years
A dog owner has been fined £1,170 after RSPCA inspectors discovered that his Labrador was so fat it found it difficult to walk.
The 10-year-old animal should have weighed around 25kg (4st) but was 70kg (11st) when animal officers visited its home in Beaumaris, Anglesey in March.
Holyhead magistrates also heard that the dog, called Ben, had a severe neck wound that needed urgent treatment.
Melvyn Davies admitted four charges of causing unnecessary suffering.
The court was told that the dog was not being kept in decent conditions when RSPCA inspectors visited Davies' home, and was clearly in need of veterinarian attention.
"It was grossly overweight to a stage that it was causing the dog suffering," said prosecutor James Conod.
"These difficulties were obvious. Clearly, it should have been seen and treated."
Mr Conod said Ben's owner told inspectors that the dog had "short legs" and was the "runt of the litter" which made it difficult to exercise the animal.
But Dylan Lloyd Jones, defending, said Davies had tried to help the dog.
"He was an extremely big dog, a dog who would at times would refuse to go out, even when Mr Davies used his best endeavours to get him out of the door," he told the court.
However, he added that Davies did accept that the dog had not received the medical treatment it required.
But he described his actions as a "one-off aberration", by a man who had kept dogs for 40 years without incident, and he was "genuinely remorseful".
The court also heard that Davies had another 10-year-old Labrador which was in perfect health, and which the RSPCA inspectors had been happy to leave in his care.
In addition to a fine, Davies was also told that the dog would not be able to return to him.
Instead, the animal is being cared for at an RSPCA foster home in Colwyn Bay.
Speaking after the hearing, RSPCA inspector Kevin Paton said it was an extremely unusual case.
"It is the worst case of obesity I have seen in a dog in 35 years of being in the RSPCA," he said.
"Hopefully, the level of fine should send a clear message to people that sometimes overfeeding a pet is as bad as starving one."
Ben is now on a strict diet in his new home, and so far has lost 24kg (3st 11lb).