That included race favourite Blue Hope and the well-supported Royal Obidos.
In an earlier separate incident longshot Frankincense reared in gate 10, hooking a leg over the front of the barrier.
As soon as attendants freed that horse a vet check saw it scratched at 4.32pm, two minutes past the official race start.
Rhyming Verses, in the next gate, was also backed out and vet checked but given the okay to race.
No sooner had the starter got back on his platform for the second time Blue Hope lashed out in its stall, spooking Royal Obidos in the adjoining gate.
That horse went down in the barrier, unseating apprentice jockey Rose Pearson, before forcing its way under the gates, pulling its saddle down over its haunches at the same time before bolting down the track.
It was not caught by the clerk of the course until the 400m mark, where it was held for assessment by the vet and it was immediately scratched.
Soon after it was taken from the course by equine ambulance and Rose Pearson was given the all clear by medical staff.
The remaining nine horses were kept in hot conditions behind the starting gate for about 20 minutes and after all being vet checked, Blue Hope was also scratched at 4.47pm.
Minutes later the starter got onto his platform for the third time and the race finally began, with the well-supported Kobe Princess delivering on recent good form (a win at Kyneton on November 16 and strong second at Yarra Glen on December 21 after no luck in the running) to take the race.
In better news from the day trainer Luke Oliver landed a double — first with Hunamosa in the $25000 Seymour Toyota Handicap over 2200m and with Kobe Princess in the gutted field in the next race.
Jockey Damian Thornton also won two, with Happily To Be in the $26000 Kelly Country Homes Plate over 1400m and Necessitas in the $26000 Avenel Equine Hospital Plate over 1600m.
Despite a strong presence from Seymour trainers and riders none of them managed to score a win on the day.
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