Well... the example ran away like this: "If there was a fire and I was given the option of saving just the cow or just the person, I would save the cow". Presumably it would be the same with a pig or a dog.
This is a trasposed version of the trolley situation: 'I would not actively kill any human, but given the choice, I consider a cow to be more valuable'.
The motivating reason was something on the line of "humans are inherently evil, while animals are incapable of evil".