Having held finance and economist roles at Fonterra and DairyNZ respectively, he now works as the General Manager of Milk Supply for Happy Valley Nutrition.
Mounsey, whose success in dairy has been six generations in the making, has been involved in the farm from a young age.
After graduating, he bought into the family business as an equity partner and was instrumental in the move from a Friesian-cross herd to Jerseys.
"It was a no brainer – the contour and soil structure of the farm we were on at the time was suited to a smaller animal," he said.
"The Jersey herd we looked at was doing similar production to our Friesian-cross animals, on a once-a-day system with a lower maintenance feed requirement."
In 2016 Mounsey bought the herd and went sharemilking on the family farm south of Otorohanga before moving to the current farm at Te Kawa last season.
The simple, low input system keeps labour costs low, with a farm manager employed to support the day-to-day running of the business, and an extra labour unit utilised over calving and mating.
"The herd is once-a-day for the first three weeks of the season to take the pressure off over the peak of calving. We then move to twice-a-day before transitioning to 16-hour milkings in November at the end of AB and back to once-a-day in December for the remainder of the season," Mounsey said.
The herd averages an impressive 86 per cent six-week-in-calf rate and around a 5 per cent empty rate from an 11-week mating, comprising five weeks of AB and six weeks with Jersey or easy calving beef bulls.
Even more impressive is the fact that no intervention is used to achieve these results.
"Jerseys are particularly fertile with the shortest calving to first service interval. Being once-a-day also helps with fertility as our cows have less pressure on them and maintain good condition throughout the season."
Mounsey selected high BW Jersey bulls from CRV with a focus on strong udders, good liveweight, stature and milk composition.
"Production averages around 350kgs milk solids per cow and inputs are limited to 150 tonnes of maize with a small amount of hay and silage made on-farm and brought in from a run-off," he said.
"Jerseys are highly efficient converters of feed to milksolids and give the best return on a per kilogram of dry matter basis."
Mounsey described the herd as low maintenance with very few animal health issues.
"We have very few cases of lameness or mastitis, and our somatic cell count typically averages less than 150,000 for the season."
The herd's outstanding health and reproductive performance also resulted in savings on young stock.
"We average 18 per cent replacements because of our low empty rate and having little need to cull on health traits, which means we have lower rearing and grazing costs than many," he said.
Mounsey said he was focused on growing the business, and looked at opportunities as they arose.
The recent purchase of 28 hectares next door to the farm will provide the flexibility and security of growing maize and silage, with the option to winter cows if needed.
"I'm always looking at ways to refine and simplify the farm business," he said.
"The purchase of the additional land means that we are insulated from fluctuations in feed prices, and we can double our inputs for roughly the same cost spent on feed at present."
