http://www.google.com/patents/US3376198?dq=3,376,198
This patent is on the use of cow udders to produce vaccines – it was found in the 50’s that by introducing an antigen into the lactating udder, the milk provided antibodies. Various salmonella were tested, Herpes, Pneumococcus, Staphylococcus…
“Since the mammary gland of the cow will produce specific antibody against any of the antigens named herein, milk may be prepared with protective principle useful against infectious disease organisms and other antigens in animals. Specially prepared milk containing specific antibodies against specific, although rare diseases, and other specific antigen induced conditions may be produced. For example, protection from ragweed pollen is offered by consumption of milk with a high protective principle against ragweed pollen.”