The powerhouse Australian owners are striking success and building their numbers with Oamaru trainer Phil Williamson.
Although their racing relationship is at a relatively early stage, it has already achieved national honours.
The Rosatis' trotter, Zoey's Gift, set a 2400m mobile national record for 3yr-old fillies when scoring her maiden win at Winton on Saturday. The Phil Williamson-trained and Matthew Williamson-driven filly's time of 3.03.5 took half a second off previous holder Jen Jaccka's mark.
The previous record was set on the same track and at the corresponding meeting in 2015.
Zoey's Gift could grab more national headlines for the Rosatis and Williamson later this month.
Williamson has the group 2 New Zealand Trotting Oaks on March 31 in mind for the filly.
''That is the plan. Whether she will be competitive or not is another thing.''
''She is only 3 once, so we are going to run and give it a go.''
While Zoey's Gift has a motor and a reputation to foot it with New Zealand's best 3yr-old trotting fillies, there are two factors that could work against her.
The first of those is her manners. She was slowly but safely away in Saturday's win, but it was the first time she had trotted throughout an official race.
''She is a work in progress. We have definitely have to get the early part of her gait improved out of sight or we won't be competitive.''
The other factor against her is maternal. Zoey's Gift is showing strong staying ability at this stage of her career, much like her group 1-winning dam Jasmyn's Gift. Jasmyn's Gift was a dual group 1-winning trotter over 2600m, but failed in the 1950m New Zealand Oaks when she was 3.
''She is very like her mother.''
The relationship between Zoey's Gift's owners and trainer started just over one year ago, at the 2016 yearling sales. The Rosatis bought an Angus Hall yearling from Jasmyn's Gift, offered by Phil and Bev Williamson.
The owners then asked the Williamsons to train the horse for them. The horse has been renamed Cavalier Stride and has shown ability, but will not be raced as a 2yr-old, Williamson said.
Later after the purchase, when watching some video trials online, the Rosatis spotted Zoey's Gift's qualifying performance and inquired about buying her, too.
A fortnight ago, the owners added two more horses to the Williamson barn.
The Rosatis, under their E & M Stride Corp banner, bought two more Angus Hall yearlings from the 2017 yearling sales.
The first buy was a $32,000 purchase, lot 309, a half-brother to seven-win trotter The Bog.
The couple backed that up with a colt from the family of Ididitmyway, lot 459 for $35,000.
Williamson trotter Davey Mac was beaten by a neck when second in the December qualifying trial that caught the eye
of the Rosatis.
The pair were both more than 12sec under the required qualifying time.
That gave Davey Mac a big reputation, like Zoey's Gift, and punters were eager to follow him when he lined up to race. That has not happened yet and is he is unlikely to race until next season.
Over the Christmas period, Davey Mac cut his leg in a paddock mishap that required stitching to heal the wound.
Although the leg is full recovered, Williamson said he was taking a patient approach and not rushing the horse, named after Southern commentator Dave McDonald, back into training.
-By Jonny Turner
