That is the experience of the long-serving AgResearch Invermay scientist who has been at the forefront of some of the most significant genetic-based productivity gains in farm livestock in recent decades.
That research has varied from helping map the cattle genome and a draft version of the sheep genome to identifying various genetic traits in sheep, including for muscling and parasite resistance.
"It is scary when you start talking time frames. You have got to think where you want to be in five years and work out how to get there," he said.
The fruits of his labour do hit home for Mr McEwan, who was raised on a sheep and beef farm near Tokanui in Southland and still has family involved in agriculture.
An interest in genetics was nurtured early by following the progress of his father's Romney sheep stud, so it was not surprising he headed to the University of Otago to study biochemistry and chemistry.
After a brief period teaching mathematics and science at James Hargest High School in Invercargill, Mr McEwan started a temporary position as a technician at the Woodlands Research centre in Southland, working on trials involving sheep and lamb feeding and sheep production selection based on genetics.
After 18 months he was appointed a scientist at the site and began working with George Davis, Hugh Hawker and Peter Fennessy.
Soon Mr McEwan started overseeing his own research, looking at lambing dates and estimating the heritability of parasite resistance and its correlation to various production traits, work he said started something of a thread he was to follow through his career.
In 1985, he spent a year at An Foras Taluntais, Ireland's equivalent of AgResearch, looking at how the Texel sheep compared with other breeds and the effects of some chemical compounds on animals.
On returning to New Zealand, he moved to Invermay to continue working on lean-sheep breeding and return to working with others on internal parasite resistance.
This led to the establishment of WormFEC.
"That was probably the first [time] I felt I'd taken something from the start right to when it was commercially applied."
In 1994 his work split into two strands.
The first looked at how to improve the rate of genetic progress on lean and meaty sheep using the CT scanner with Neville Jopson, and he was also involved in calculating breeding values with farmers.
This, along with work by other scientists such as Sheryl-Anne Newman, would contribute to the creation of Sheep Improvement Ltd (SIL).
Initially there was some concern about making it a web-based system.
"It sounds strange, but in 1996-97 an internet-based system was a pretty big leap of faith."
In 1999, SIL was launched. It grouped carcass confirmation through the CT scanner and Inner Vision, WormFEC and cross flock evaluation.
SIL was to deliver the greatest productivity gains to farmers Mr McEwan had been involved with.
Other genetic schemes flowed off that, such as the central progeny test started by Alliance Group and taken over by Beef and Lamb New Zealand.
Genetic gains from SIL are estimated to have added between 30c and 60c per ewe wintered per year, with central progeny tests and other tools adding another 60-90c.
The second thread of his career was a joint venture with the University of Otago to develop a molecular biology unit which built a "crude" map of the sheep genome and discovered, with George Davis, the Booroola and Inverdale prolificacy genes.
Subsequent DNA sequencing funded by Ovita has led to the commercial release of tools such as Mio Max and Loin Max, muscle-determining genes in Texels and Dorset and other genes to determine parasite resistance and blindness in Texels.
As for the future, Mr McEwan is working with the Pastoral Greenhouse Gas Research Consortium to look for a genetic solution to reducing methane emissions from livestock.
The quest for productivity gains from genetics promises even greater riches, and Mr McEwan believes annual productivity gains double that achieved so far could be possible within five years.
"It is achievable, but we have got to get industry adoption and do a bunch of research to make sure it happens."