Music legend Paul McCartney has called on a US 'pet blood bank' to release around 150 greyhounds who are 'suffering in squalor'.
The Pet Blood Bank generates canine blood products for veterinary transfusions across the States.
As the company was unable to sustain its output using volunteers and a bloodmobile, it started using retired greyhounds, who are kept in kennels on a private farm.
An exposé by animal rights group PETA revealed grim conditions: dogs were emaciated, with overgrown claws, and bad teeth.
Patterson Veterinary, which operates in the UK as National Veterinary Services Limited, distributes the products from The Pet Blood Bank, Inc in Texas.
Patterson Veterinary promised to support efforts to ensure the dogs' care
But less than a week later, the company reneged on the promise, prompting McCartney to send a letter on behalf of animal rights charity PETA US calling on Patterson's billion-dollar parent company to step up and help rescue the dogs.
"I have had dogs since I was a boy and loved them all dearly, including Martha who was my companion for about 15 years and about whom I wrote the song 'Martha, My Dear,'" writes McCartney.
"I join my friends at PETA in asking you to pay these greyhounds back, and to let them retire from the dirt-floored, barren conditions in which they are kept isolated and alone."
According to PETA, dogs at The Pet Blood Bank 'were denied veterinary care for severe oral infections, painful and infected wounds, an apparent broken leg, and other health issues'.
A spokesperson added: "Most canines at the facility are solitarily confined to barren kennels, in which they display severe stress-induced behaviour patterns, including pacing, spinning in circles, cowering, and even urinating on themselves in fear when approached.
"Since PETA US' exposé was published, more than 110,000 people have urged Patterson to use its resources to secure lifetime care for the dogs, and a mobile billboard has appeared outside the company's Minnesota headquarters."