Ann, who lives close to Selby Abbey, said: "I'm very upset – furious. They just put Nightshift down as if he was so much rubbish. They tried to justify it by saying he was old.
"I told them well I'm old too! Then they said he had most of his teeth missing. Well, I have no teeth at all! It was just like something out of Nazi Germany."
Ann said Nightshift had been taken ill and was treated at a highly-regarded vets in Howden on August 30 for respiratory difficulties.