The course was declared unsafe following an inspection, with trainers, jockey and race officials taking part.
The Scottish track had been hit by more than an inch of rain on Tuesday and with more falling during the afternoon conditions changed from soft to heavy soft in places after the first race.
There was no let up in the weather and the decision was taken to cancel the last five races.
"Jockeys came in after the third race and reported they felt a bit of false ground. We had a look but it just seemed to be a wetter area, a heavier patch," clerk of the course Graeme Anderson told Racing TV.
"They came back in after race four and reported a couple of areas, one about the furlong-and-a-half mark and one about just the half-furlong.
"We had a look. They were pretty deep holes, just really heavy ground. We'd had eight millimetres since 12.30 today on top of 28mm yesterday. It's been relentless so it's taken its toll.
"It's right in the centre. We looked at trying to run the races on the round course and abandon the sprint race, but there's a fear you can't avoid it during a race. It was better to be safe than sorry."
Anderson said it was a different part of the track to where they had experienced problems in the past.
"It's an area where we've never had a problem before," he went on.
"It just seems to be wetter than others and just holding water and the holes are starting to fill with the rain coming down. It's going to ride false.
"It's unrepairable at the moment with the rain coming on top of it.
"I'm hoping it's just a case of the amount of rain we've had and it's nothing more than that, but we will definitely be investigating and see what caused it and see what it's looking like.
"It's two weeks on Monday for our next meeting and then the Gold Cup meeting about three and a half weeks after that."
