Colds in the Cowshed – Researchers Declare War on Pathogens
It starts with a scratchy throat; your head throbs and your eyes burn. But not only we humans suffer from such symptoms as coughing, a runny nose and a sore throat in the autumn – colds are among the most common illnesses among cows, too, at this time of the year.
As it cools down outside, a wave of colds rolls through the cowshed. Overheated rooms and poor ventilation further accelerate the spread of the pathogens. Young animals are worst affected. In calves younger than four months the immune system does not yet fully function, and there is little it can do to fight off infections.
The farmer has to call the vet as soon as he recognizes the first signs of a cold – sniffing, coughing or even fever. A detailed examination will reveal which pathogen is responsible for the illness. It is often caused by bacteria, and they can multiply extremely quickly. Like us humans, the calves are given medication when necessary so that they can recover quickly and don't infect more young animals in the stable.
Pharmaceutical researchers have to work long and thoroughly to ensure that a veterinary drug is effective against such aggravating pathogens and that it does not harm the cattle at the same time. "Once we have found an active substance that successfully combats the bacteria, the work in the laboratory really gets going," says Dr. Hans-Robert Hehnen, researcher at Bayer HealthCare. Before a new veterinary drug can be used, it has to pass through a development stage of about ten years. In the EU, substances can only be marketed if they meet the EU's high standards and have been tested by independent experts from the regulatory authorities.
Among other things, pharmaceutical researchers must find out beforehand how much of the active substance is needed to completely eliminate the pathogens. To do this, different species of bacteria – rod-shaped, round or spiral – are placed into dishes with small depressions. Then a laboratory technician uses a pipette to drip a certain amount of the active substance onto each type of bacteria. The dishes are then placed into a special incubator for one to two days; the weakest of the bacteria already disappear after a few hours. Others survive the test substance and need a higher dose. The right amount of active substance has been found when there are no bacteria left in the dish.
"Our laboratory tests also examine drugs in what we call an artificial stomach," explains Bayer researcher Hehnen. "This device simulates the animal's stomach. It contains an artificially produced gastric fluid, and a mixing mechanism imitates the natural movements of the stomach. This enables us to determine how long it takes until a drug – whether in capsule or tablet form – is dissolved by the gastric acid." In this way the researchers determine the best form for administering a drug. Only after all the lab tests have been carefully carried out, and the authorities have approved the drug for marketing after another examination, can it be used on animals.
Apart from having a rapid effect on the sick animal, another high priority for the research company is that the drug is broken down as quickly as possible again by the animal's body. After all, the farm animals ultimately produce food for us humans – and this food must be free of potentially harmful substances. Only after a certain waiting period may food again be delivered from animals that have been treated.
