A witness has told a jury that the relationship between Scott Guy and the man accused of shooting him dead soured after he married Mr Guy's sister.
Ewen Macdonald is on trial at the High Court in Wellington charged with the murder of his 31-year-old brother-in-law at his Feilding farm on 8 July 2010.
The Crown says Mr Macdonald, 32, was concerned about inequalities he perceived in the amount of work he and Scott Guy had to do around the farm and tension arising from that led to the killing.
However, the defence says while Mr Macdonald acknowledged that he had damaged property belonging to Scott Guy and his wife Kylee, that did not make him a murderer.
Farm consultant Simon Redmond told the court on Monday that when Ewen Macdonald became dairy manager and took more responsibility the accused and Mr Guy began to drift apart.
Mr Redmond said Mr Macdonald made some negative comments about Mr Guy and had a less positive attitude towards him. This occurred well before the farm was restructured in 2008 giving Ewen and Anna Macdonald and Scott and Kylee Guy a 10% share each.
Mr Redmond said both men were on similar pay packages, but Mr Macdonald had better skills and a better work ethic than Mr Guy.
He said Mr Macdonald referred to Mr Guy's bravery after he died and thought it was a reference to his prowess at bull riding.
Manawatu farmer Andrew Short also gave evidence on Monday, telling the jury he noticed competitiveness between Scott Guy and Ewen Macdonald.
Mr Short said towards the end of his school days he did weekend work on the Guy farm where he met Mr Guy and Mr Macdonald.
He said the relationship between the two men ran hot and cold, and he noticed a competitiveness between them which he didn't experience when he was farming in partnership with his own brother.
Farmhand says accused great boss
In other evidence on Monday, former farmhand Jackson Gilbert told the jury that Ewen Macdonald was the best boss he had ever had.
Mr Gilbert worked on the Guy farm for just over a year when he left school and said the place had "a good vibe".
In reply to questions from defence lawyer Greg King, Mr Jackson said he could sense a rivalry between Scott Guy and Ewen Macdonald, but it did not get in the way of productivity or affect the mood on the farm.
Farm worker Matthew Ireland told the court of meeting Mr Macdonald on the day Scott Guy died.
Mr Ireland, who was on work experience at the Guy farm, said he arrived early on 8 June 2010 and shortly afterwards Mr Macdonald walked past, wiping his eyes and looking as though he had just woken up.
He said he asked if Scott Guy had slept in, and they had a laugh about that because Mr Macdonald told him Scott Guy had slept in before.
Mr Ireland said he went back to the farm later in the morning. A roadblock had been set up and he heard Mr Guy was dead. He said when he arrived for milking a car went past the property, which was an unusual sight that early in the morning.