Wagtail
Horse servant
Surely it's better too eat dead animals than waste them - all drugs are supposed to be on the passports.
But they are not. The only time I have ever had my passport looked at by a vet was when I have taken them to Rossdales, or just to stamp the vaccinations page. Vets maybe supposed to note down all drugs on passports, and owners are supposed to sign the back saying that the horse must not enter the food chain, but this very rarely happens unless the horse gets referred to a major equine hospital.