Newer technologies for vaccine development and delivery may further enhance the production of immune milk products. Immunization protocols that expose animals to specific antigens may enhance humoral immune responses in the mammary gland, including peptide-based vaccines [108] , and DNA-based vaccines [109, 110] . Delivery of antigen to the animal can also be achieved with antigen encapsulated in biodegradable microspheres [111] , and with antigen-release devices [112] . Transgenic animals also have been used to produce antigens that then may be used to vaccinate animals against viral disease [113] .