"It is always a struggle to get calves on and off the trailer, which becomes a staff health and safety issue," says Mr Caldwell.
"Plus, on a cold, wet day you have all the newborns shivering, so there is that desire to get them to where it is warm as quickly as possible."
Mr Caldwell had an idea for a system where the calves were suspended so they couldn't fall and get hurt.
He mentioned his concept to engineering mate Greg Kane of Matamata and the pair experimented until they came up with the Moova.
It is a trailer designed to carry 20 calves at a time, each in a sling that is the right height to make loading easy for workers and keep the calves safe.
The Moova is aimed at large operations of more than 400 cows, but Mr Caldwell says it can be modified to suit differing needs.
Initially the pair produced a crude prototype using two pipes, four cable ties and bit of milk liner.
Mr Caldwell says it worked - but it wasn't suitable for transporting.
Mr Kane says they experimented with various materials for an alternative sling - a calf-meal bag, bits of a 200-litre plastic drum and even part of an old pond liner.
"The pond liner worked really well," says Mr Kane.
"We knew we were on track and we built a the trailer to suit."
Calving was underway by the time they had the first Moova built and it went straight into trial. Mr Caldwell used it to pick up 600 calves. He says it was faultless and the team went from numerous trips per day to just three.
"It was quick, safe and efficient."
To make sure, the Moova was trialled on two other farms, with continued success. And other advantages came to light.
While loaded into the Moova's slings, calves can be tube-fed, eartagged and have their navels sprayed. Mr Caldwell says the feedback from farm use has been positive and the Moova is exceeding expectations.
The inventors say the Moova was designed to be practical, ergonomic and humane - and it is.
The Fieldays Innovation Centre provided a platform to spread the word, and with pressure on farmers to comply with new rules about animal welfare and health and safety for workers, it attracted a lot of positive feedback.
Winning the Crowe Howarth Innovation Award, recognising excellence in animal welfare and health and safety, confirmed that success.
They won $5000 worth of help and advice from accounting and consulting from Crowe Howarth, which will be used to take the Moova into the next phase of production and marketing.
For more information email themoova@mail.com.