By combining genes from different organisms, via recombinant DNA techniques, transgenic animals have been developed. Whether this costly technology becomes used in mainstream agriculture will depend on capability establishing new traits in animals that cannot be incorporated by any easy method. Some potential benefits to the livestock industry by using transgenic animals are: more efficient nutrient usage as fewer nutrients will be lost in the feces, altered milk composition that provides all desired nutritional components, and improved immunity to disease. This study is attempting to reduce mastitis in dairy cows by manipulating the mammary gland cells to secrete more antibacterial proteins. This has already been achieved in mice, as they secreted higher levels of the protein lysostaphin in their milk. When this protein is secreted with the milk it improves the mouse’s resistance to Staphylococcus aureus, which is a major cause of mastitis in dairy cows. Currently other antibacterial proteins are that can work complementary to lysostaphin are being sought after. The benefits of having the antibacterial proteins in the milk, is that it will reduce the use of antibiotics currently used to treat mastitis. Injecting or ingesting the antibacterial proteins has proven to be ineffective, as the body’s immune system will destroy them because they are a foreign protein or they are broke down during digestion. However, if the animal produces the protein itself it prevents the immune system from breaking down the protein. Research is also underway to try to limit lysostaphin production to only when it is needed, during an infection with mastitis. The incorporation of transgenic animals into the agricultural industry could be very beneficial but before they are incorporated the DNA used and the animal that is produced from the altered DNA must be extensively studied.