Milk does not come from purple cows, and steaks and hams are not manufactured in a factory: these foods come from real cattle and pigs. And much is already done on the farm to ensure good quality. Professionally trained farmers and vets regularly check the health and welfare of farm animals. But cattle and pigs can still fall ill despite good care. For example, if pigs catch cold or have diarrhea, they feel unwell and need swift help – just like us humans. The four-legged patients sometimes also need medication – in their case from the vet. Great care must be taken in the selection and dosage of the drugs. The vet not only looks after the health of the sick animal, s/he also ultimately has a responsibility for the safety of our food.

But steps are already taken in the research laboratory during the development of a veterinary drug to make sure that consumers later receive healthy food. Professor Heinrich Greife, animal-health researcher at Bayer HealthCare, explains: "In the development of veterinary drugs we do our best to ensure that the animal recovers quickly. Moreover, the drugs should leave the animal's body as quickly as possible once they have had the desired effect. Only then are meat and milk from these animals suitable for human consumption."

 Drug developers carry out research and tests for about ten to fifteen years before a newly developed drug can be used to combat an animal disease. The key ingredient of any drug is the active substance, i.e. the ingredient that has the healing or relieving effect in the animal's body. To find this drug, the pharmaceutical researchers must first find out what it has to be like. "A drug can, for example, combat a specific pathogen directly. But there are also substances that support the animal's body in such a way as to enable it to resist the disease itself. Once the optimal active substance has been developed, we test it to find out how much of it is needed and how long it has to be administered to cure the disease," explains Professor Greife. Apart from determining the perfect dose, they also investigate how long the individual substances remain in an animal's body, to ensure that foodstuffs that are later made from the animal are safe. After being treated with drugs, therefore, the animal not only has to be completely restored to health; a certain waiting period must also be complied with before milk and meat is allowed to be delivered by the farmer and consumed by us.