RSPCA prosecutor Malcolm Caulfield said Rosebery man Trevor Hilton Brew pleaded guilty in the Queenstown Magistrates Court on Tuesday to a charge of animal cruelty.

Mr Caulfield told the court Brew was drunk when he cut the dog, which he had since it was a puppy, across the throat.

Mr Caulfield said Brew's crime was first reported by his partner on May 8, who came home on April 30 and found the dog bleeding.

"[His partner] said Mr Brew had cut the dog's throat with a knife... [and] took the dog to a veterinary surgeon at Burnie," Mr Caulfield said.

On May 21, an RSPCA animal welfare officer interviewed Brew, who said he was the owner of 20-month-old Thor, the court heard.

"He had got annoyed with the dog when he was drunk because he had been playing with it and it had become aggressive.

"He got a knife and cut the dog across the throat."

Mr Caulfield said the Burnie veterinarian provided a statement to the court, in which she said she had treated Thor on April 30.

"The wound was recent and actively bleeding," he told the court.

"It was a three centimetre cut one to two centimetres in depth.

"Dr Sheppard said it was necessary to suture the wound, and that if it had not been sutured it would have continued to bleed and the dog would have continued to lose blood.

"She said blood loss can lead to clinical illness, shock and even death."

The court heard the injury was so serious the dog needed to be anaesthetised during treatment.

Deputy Chief Magistrate Michael Daly said Brew's crimes were a "confronting way of inflicting animal cruelty" and that a penalty needed to reflect the seriousness of the offence.

Brew was sentenced to two months jail, wholly suspended for two years.

He was further fined $2000 and disqualified from owning a dog for three years.