The new O'Leary 60-bale rotary is expected to crank into gear by early next month.

Michael and Lynette O'Leary have bucked the trend and invested heavily in an industry some claim has passed its peak.

The couple have invested $1.5 million in a new state-of-the-art milking shed on their Whangaehu dairy farm just south of Whanganui.

Despite the naysayers claiming the dairy industry may have reached its peak and, in fact, is on the wane, the O'Learys are more than happy to invest substantially in an industry that has been their bread and butter for several generations.

Michael, of course, is one of the four brothers that famously raced the multi-million dollar earning racehorse Who Shot Thebarman recently retired to the Legends property in Australia.

Despite the millions earned by their popular thoroughbred, Michael and Lynette say none of those earnings have gone toward paying for the new shed.

"We wouldn't mind another horse like Barman to help pay for the new shed, though," Michael lamented.

"We are confident the industry has a bright future and this state-of-the-art 60 bale rotary is the future."

While it is by far the most ambitious build he has ventured to undertake, he is no stranger to upgrading milking sheds.

When in partnership with brother Shaun the pair upgraded around six cowsheds beginning with their late father's original. The brothers have now been farming individually for the past 10 or 12 years and the last upgrade was some 20 years back.

"This is a fully computerised shed capable of collecting and collating all sorts of data on each cow's production and health and then delivering remedies or altering this to increase production."

The O'Learys still have their old 60-bail herringbone milking shed that has been reduced to a 30-bail operation designed to cater for cows with special needs.

In a Herald story last week reporter Jamie Gray said the number of cows in New Zealand was static or declining and dairy conversions had slowed to a virtual standstill - so asked is the country's biggest export industry past its peak?

Reports from regional councils suggest that the number of properties being converted into dairy farms has slowed to a trickle, remained static, or gone backwards in some areas.

All up, it looks as though the area of land devoted to dairy may be shrinking.

Milk production has also stopped increasing. It hit a record in the 2014/15 season, when 1.89 billion kg of milksolids was produced.

Production has since wavered just below that figure, at the 1.85 billion kg mark.

In the season just finished, the figure was 1.88 billion kg.

Over the same period, the number of dairy cattle has dipped. Last year there were 6.4 million animals in the national herd, compared with the 2014 peak of 6.7 million.

Dairy remains by far New Zealand's biggest merchandise export, worth $14.1 billion in the year to last June.

And despite the signs, ASB senior rural economist Nathan Penny says it is an open question whether production has peaked.

"My personal view is that we are not there yet," he says. "If we can increase productivity or even hold production and decrease inputs, then that would be a good result.

"With technology and better genetics we could end up with fewer cows and more milk," says Penny.

"It is very possible and it would be a good result if we can do that because the world still needs more milk."

This is the same attitude Michael and Lynette O'Leary have adopted.

There is also an added bonus with the new shed - there is now no need to get out of bed at 4am to milk cows.