Mr Cooper (52), whose surprise resignation was announced yesterday after seven years in the top role, said the time was right for change.
His announcement came alongside confirmation the company would be returning to profitability this year.
It was timely to step down with the company ''back in black'' and also embarking on various new initiatives where new levels of energy were needed, he said.
He leaves as one of the highest-paid chief executives in Otago, with figures in last year's annual report showing he earned between $970,001 and $980,000.
Dean Hamilton, who joined SFF as chief strategy officer in April, has been appointed interim chief executive. The handover process would be completed by the end of the year.
Asked what he intended to do, Mr Cooper said he would be looking at opportunities, whether that was in consultancy project work or directorships - ''that type of thing''.
Those opportunities would not be the ''24/7'' role of chief executive of a big company, with its ''challenges, trials and tribulations''.
Mr Cooper, who also has a farm at Middlemarch, was looking forward to some time out, saying the new year would be a new beginning.
''Who knows what's around the corner?''
Mr Cooper has worked at Silver Fern Farms since 1989, then known as PPCS. He was appointed chief executive in 2007.
His previous roles included chief operating officer and chief executive of UK operations.
Asked the highlights of his tenure, Mr Cooper named putting together the merger proposal with PGG Wrightson which turned into a lowlight when it failed.
Establishing Getting FarmIQ and the beef Eating Quality system were also highlights.
Along with the low point of ''a couple of bad years'', he was also disappointed no progress had been made with industry model changes.
He had been ''party to some big ideas'', none of which had been implemented.
The most common theme talked about ''for years'' was the industry needed to consolidate 80% of red meat processed and marketed ''in one place''.
But he questioned where that figure came from and where the proof was that it would deliver a different outcome.
He cited Fonterra, which controlled 88% of the dairy industry, yet was not able to stop the recent dairy price slide.
Silver Fern Farms chairman Rob Hewett said Mr Cooper had made a ''significant contribution'' to the business.
As chief executive, he had led the creation of the SFF brand, coupled with implementing the value creation strategy which covered the consumer range, commercialisation of the beef Eating Quality system and FarmIQ.
The board thanked Mr Cooper for his committed service and his expertise in leading the company through some ''significant challenges''.
''We've come out of two years of very average results, to put it mildly ... Keith's got the boat steering back where we want it to go,'' Mr Hewett said.
Federated Farmers meat and fibre chairman Rick Powdrell said Mr Cooper's ''larger than life'' personality would be sorely missed.
''Like all of us, Keith was not without his faults, but here was a guy who at least had a vision for the red meat industry and was prepared to back himself and Silver Fern Farms.
''One thing about Keith is that you knew where you stood with him,'' Mr Powdrell said.
Mr Hewett said Mr Hamilton brought extensive financial and operational senior leadership experience, as well as a good understanding of the business.
