A 23-year-old woman showed "callousness almost beyond belief" in her treatment of a female boxer cross, a Launceston magistrate said in sentencing on Tuesday.
Skye Harris, of Mayfield, was found guilty of one count of cruelty to animals in a hearing she failed to attend.
Harris had failed to feed and provide water for the boxer cross "Smooch" but had otherwise treated her own dog "Roxy" adequately.
Magistrate Simon Brown fined Harris $1500 and banned her from owning any dog other than "Roxy" for seven years.
He said the story had a happy ending because Smooch thrived when seized by the RSPCA.
He also granted an order in favour of the RSPCA for the costs of $2867.06 to care for the dog.
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He dismissed a count of management of animals that resulted in pain and suffering because Harris had inherited the dog from a family member who may have also have failed to feed the dog in preceding weeks .
"Photos showed the starkly appalling condition in terms of nutrition and hydration," he said.
"It appears to have been malnourished for some considerable period of time."
The dog had been confined in an area with extensive buildup of faeces and urine.
He said the defendant's failure to care had caused the animal to suffer significant pain and distress.
"The defendant showed a cavalier disregard for this animal's condition over a period of weeks," Mr Brown said.
The case was heard in the Launceston Magistrates Court.