Milk Quality and Udder Health

Abstract

When natural defense mechanisms fail to prevent invasion of the mammary gland by microbial pathogens, intramammary infection and mastitis may occur, producing illness, decreased milk production, and decreased milk quality. The presence of mastitis in a dairy cow may be detected by clinical signs such as abnormal milk and mammary swelling, or in the absence of clinical signs by increases in the cell population or conductivity of the milk. Decisions about whether to treat a particular case of mastitis and how to control and prevent mastitis in the dairy herd are more easily made when the pathogen or pathogens responsible for the infection are identified. Definitive identification of mastitis pathogens is made using microbial milk culture. Depending on the objectives ofthe practice and the level of motivation and training of the staff, there are various levels of investigation that may be undertaken, from only identifying the presence or absence of pathogen growth and whether pathogens are gram negative, to culturing for mycoplasmas and running further tests to identify certain bacterial genera or species. Whatever protocol is established, it is important to also establish practices for quality control to ensure accurate results. A milk microbiology laboratory in the veterinary clinic provides an excellent opportunity for expanded client services and professional development of the veterinary technician.