Ms Bosma spotted Pepper, a 16.3 hand Clydesdale cross, on the Echuca saleyard horses Facebook page in November last year.
Hundreds of horses are auctioned off at the Echuca saleyards in Victoria every second Wednesday, with many destined for the meatworks.
But a group of dedicated volunteers go down the night before to take photos of the horses and have them vet checked in the hope they can find loving homes.
Among the hundreds of horses that had their photos posted online was Pepper.
Ms Bosma said she wanted to start riding again and decided the eight-year-old mare with a quiet temperament would be the perfect horse. She also thought Pepper, who had given birth to four foals, was in need of some attention.
“During the sales, someone bids on your behalf while you’re on the phone,” she said.
Pepper travelled from Victoria to Adelaide, Adelaide to Kalgoorlie and then finally to Byford.
“We did some training with her as she had been in the paddock for a long time and she was going really well,” Ms Bosma said.
Pepper continued to progress but Mrs Bosma thought she was too big for her to ride.
The WA Mounted Police Section took her for a trial at its headquarters in Maylands.
Pepper performed well during the initial trial and was in line to be the mounted police’s newest recruit. But she did not pass the vet check when a veterinarian discovered a sarcoid, a non-invasive type of skin cancer, under her eye.
Ms Bosma said it was a shame she missed out on the mounted police but she was happy to have her home.
The sarcoid will not cause her any major health issues and Pepper will live out the rest of her time as a riding horse with three miniature donkeys for company.