The victim was knocked out cold after he received a boxing style punch with full force, Mold Crown Court was told.
He fell forward onto the ground without trying to save himself – and while he was lying helpless was punched a number of times by defendant Iwan Hedd Roberts, 20.
Roberts of Abernodwydd Farm at Llangadfan, Welshpool, admitted assaulting farmer Samuel Griffiths in September of last year, received a 12 month sentence of youth custody.
Judge Rhys Rowlands imposed a two year restraining order not to approach the victim or write anything about him on social media.
The judge described his actions as “cowardly drunken violence” which could have had life threatening consequences for the victim.
The court heard that the defendant believed that the victim had been spreading rumours about a member of his family, implying that he had been responsible for recent sheep rustling incidents.
“There is, I am told, nothing to substantiate those rumours,” the judge said. The prosecution said that Mr Griffiths had not started those rumours but had simply mentioned to police what he had heard.
However, the judge said that Roberts should simply have ignored those rumours.
But after the annual agricultural show at Llanfair Caereinion Roberts saw Mr Griffiths in the pub and sought to confront him.
Both men were asked to leave and once outside Roberts threw a boxing punch from behind.
He swung his arm with full force which caused him to land head first on the pavement without making any attempt to break his fall.
The victim had bruising and swelling, his teeth were chipped and he had headaches for 11 days. Prosecuting barrister Karl Scholz said that at the end of the show Mr Griffiths was in the Red Lion public house when he was approached by the defendant at 11.30 pm who shouted that he would kill him.
It was an unprovoked and vicious attack, he said.
Defending barrister William Hingston said defendant was a hard working family man who contributed a lot to his community including the young farmers’ cub and the youth club.
Mr Hingston said his client apologised.