David Fullerton can tell before a heifer calf is weaned if it's going to grow into a profitable, high-producing dairy cow.
David and his wife Pip, along with their sons Alex and Dean, milk almost 600 Holstein Friesians at Ngahinapouri near Hamilton.
They're using genomic testing to identify calves with the greatest genetic potential, enabling breeding decisions to be fast-tracked.
"Genomic screening has been one of the biggest advancements in cattle breeding in the last 100 years," said Fullerton.
"It dramatically shortens the time it takes identify important traits in an animal from five years to several months."
Those traits vary from a cow being a more efficient converter of feed into milksolids, through to being heat tolerant.
The Fullerton's import embryos from Canada, the United States and Holland and are world-renowned for their genetics work.
Their stud, Waipiri Holsteins, holds the New Zealand record for the top registered three-year-old Holstein Friesian cow, which produced 1,292 kilograms of milksolids in the 2009/10 season.
They rear 160-200 replacement heifers a year and plan to genomic test 25 per cent of them using a service offered through Holstein Friesian NZ.
"We've exported bulls to Tanzania, China, Malaysia and South America and are exploring opportunities to sell semen into Zimbabwe, Vietnam the Philippines and Ecuador," he said.
"Most farmers in those countries can't afford cooling fans, so we need to know our animals can tolerate the heat."
"Genomic testing has huge potential to increase dairying's profitability and we'd be foolish to ignore the information it provides," said Fullerton.
Currently the annual value of genetic gain in the New Zealand dairy herd is worth around $11 per cow.
The figure is almost twice as high in Australia where the use of genomic screening is more widespread.
Genomic testing is most reliable and beneficial for New Zealand dairy farmers using semen sourced from overseas bulls.
Farmers can use the results to make informed decisions about which heifers to keep and breed from, or to sell.
"The reliability of the information provided is similar to a bull with 100 daughters which are producing milk and whose traits, such as udder conformation, calving difficulty and fertility have been assessed," said Holstein Friesian NZ president Hennie Verwaayen.
Hennie and his wife Kerri and their children Harvey and Lucy milk 380 Holstein Friesian cows near Dannevirke.
The couple first used genomic testing in 2016 on four calves born from embryos imported from the United States.
"Two of the calves were bulls. They were both almost identical to look at, but the testing revealed one was among the top five in the world for certain traits," he said.
The Verwaayen's now use the service provided through Holstein Friesian NZ to test all of their overseas-sired replacement heifers.
"If the results identify genetically superior heifers, we can do embryo transfer work with them or mate them using sexed semen," he said.
"The test has the added advantage of verifying parentage, which improves the accuracy of our records and means we don't have to pay for a separate DNA test."
"New Zealand is languishing behind in adopting this technology and our association is endeavouring to change that," he said.
In June, Holstein Friesian NZ teamed up with Weatherbys Scientific in Ireland to offer a genomic testing service.
Farmers can choose whether the data is reported through DataGene Australia or the Council of Dairy Cattle Breeding in the United States.
Animals can also be tested to determine if they will produce sought-after A2 milk and if they're polled.