The RSPCA has taken the drastic step of opening up its case files to highlight the shocking extent of animal cruelty and neglect in South Australia over the past year.

Key points: The RSPCA said rescue officers found 579 animals abandoned over the past year

The RSPCA said rescue officers found 579 animals abandoned over the past year Difficulty in tracking down the owners means only a fraction of cases are prosecuted

Difficulty in tracking down the owners means only a fraction of cases are prosecuted The worst involve severe emaciation, mistreatment and neglect

According to the organisation, 579 animals were found abandoned across the state in the 12 months to July — up from 567 the previous year.

Adult dogs and puppies account for the lion's share of that number, with 323 cases, while there were another 188 cases involving cats and kittens.

But the RSPCA said it had also discovered rabbits, reptiles, birds, guinea pigs, tortoises, ferrets, ducks, geese, chickens, cows, sheep and fish which had been mistreated or left in squalid conditions by owners, many of whom have avoided prosecution.

It has released images of the state's worst cruelty and neglect cases but is also hoping to secure new homes for some of the traumatised pets.

One of hundreds of sheep found to have been neglected on an Adelaide Hills property. ( RSCPA )

Of the most appalling cases of abandonment, the organisation said two dogs — one of which had its front legs cable-tied — were found at a Flinders Park home.

The home's owner had moved interstate and his daughter had been evicted, leaving the dogs to fend for themselves.

In another instance, a disabled cat was discovered in an Ottoway backyard after being left there by its owner who had gone to live overseas.

However, inspectors said they were often confronted by even more gruesome sights, with some of the animals deceased.

"We think it's really important for the people of South Australia to understand what's actually happening out there, and the level of neglect and cruelty that's occurring," RSPCA chief inspector Andrea Lewis said.

"Some of the injuries that we're seeing — tumours and things like that — which have been left for months and months on end have grown to the size of rockmelons.

"Unfortunately, for some animals, it is too late."

In June last year, a Staffordshire terrier called Boss was found dead and dumped in an aviary in a backyard at Burton.

Irish wolfhound Azora was found with a badly ulcerated tumour and was later euthanased. ( RSCPA )

The dog's owners received a 10-month suspended prison sentence, the RSPCA said.

"Cases like the one with Boss are absolutely heartbreaking. His death was cruel and senseless," Ms Lewis said.

"Wherever possible, we aim to educate people on how best to care for their animals — we believe this is the only way to create lasting change.

"For some owners, being reported to RSPCA and receiving a formal visit from an inspector is the catalyst for dramatic change, which improves the life of the animal currently in that person's care, as well as future animals they may acquire."

Tracking down owners makes prosecution difficult

Across the 12 months, 38 people were prosecuted in South Australia over 32 cases involving starvation and chronic neglect.

There were also two instances in which people deliberately killed dogs.

The squalid living conditions of a dog at Burton. ( RSPCA )

However, the RSPCA said those numbers were the tip of the iceberg, with 4,244 reports investigated.

"Last year, inspectors seized nearly 1,000 animals as a result of cruelty complaints and neglect," Ms Lewis said.

"We can't always locate the owners, which means we can't proceed to prosecution."

But Ms Lewis said the organisation preferred to wield the carrot, rather than the stick, if circumstances allowed.

"We're really trying hard to educate people rather than proceed to prosecution. In a lot of cases there's perhaps mental health and other issues involved," she said.

"In some cases, some people just need a bit of help. In other cases, they just need to learn how to look after their animals."

The successfully prosecuted cases included a man who kept 52 cats in squalid conditions on a property at Macclesfield, where a magpie and a galah were also seized.

Ruby weighed only 11.9 kilograms when she was seized. ( Supplied: RSPCA )

In another case, a Port Noarlunga South woman was convicted for failing to treat a Staffordshire bull terrier called Lucifer.

"Sadly, Lucifer's condition was so advanced that he stood no chance of recovery and he was humanely euthanased," the RSPCA said.

A Seaford woman also pleaded guilty over the extreme neglect of a young rabbit, which had fur so matted its hind legs were bound together.

Ms Lewis said there was a stigma around surrendering animals to animal welfare authorities — and that needed to change.

"Abandoning an animal is never OK — more humane options exist for people who find themselves unable to care for an animal," she said.

"It's far better for animals to come into the care of a reputable animal welfare organisation like RSPCA than to be neglected or — even worse — totally abandoned."