Breeder Chris Stapleton said it appeared to be his lucky number as he celebrated 49 years of marriage to his wife Pauline on the same day.
"I was pretty happy yesterday," Mr Stapleton said.
The previous record, set last year, was $35,200. Mr Stapleton had expected to get about $30,000 for Eve and was surprised by the result.
"She's a pretty good little dog and she's really well bred,“ he said.
“She was no accident, she was bred to be as good as she is."
Eve's bloodline goes back 50 years to some of Mr Stapleton's original dogs.
"She's pretty laid back and goes with the flow, she doesn't get too excited about things," he said.
"She's a very nice dog to have around because she's not hyperactive and when you need a job done, she's willing and able to do it. She's the perfect dog."
When the bids reached $46,000 from buyers onsite at Newbridge and online through AuctionsPlus, auctioneer Jason Pearce joked: "It's fair to say she's on the market".
Mr Pearce said working dogs were in high demand due to skills shortages across agriculture.
"With demand comes increasing price, like any commodity,“ he said.
“There's more emphasis on there being fewer workers, less skills, so there's a requirement for a dog to potentially do more.”
Eve's fit physique and her unique ability to work with cattle, sheep and goats attracted buyers.
"She had pedigree bloodlines, the physical attributes, she was trained at 20 months, which is quite rare," Mr Pearce said.
"She was the complete package."
Eve's new home will be at a sheep stud in nearby Oberon.
Mr Stapleton, who has about 20 dogs including pups and retired kelpies, said the ultimate reward for a working dog was a warm kennel.
"I like to keep my dogs into retirement, so I've always had quite a few.
"You give them verbal praise, and they know when they've done something well. I like to give them a pat."