Haptoglobin (Hp), an acute phase protein has been recognized as an important indicator of intramammary infections that can be assessed in milk. In this study, we utilized immunohistochemical techniques on naturally infected and healthy bovine mammary glands in order to determine the source of Hp found in milk during bovine mastitis. Mammary glands sections were harvested from udder of two cows, one showing signs of clinical mastitis and the other healthy. Hematoxylin and eosin as well as immunohistochemistry (IHC) for anti-Hp staining were carried on these sections. It was revealed that the mammary epithelial cells around the alveolar ducts of the gland as well as with infiltrating neutrophils had dense staining for Hp in mastitic sections while in the healthy section there was minimal cytoplasmic positivity for Haptoglobin on the ductal epithelial cells. These observations support the conclusion that Hp arises locally from mammary epithelial cells and from circulation from migrating neutrophils during episodes of mastitis, and can therefore serve as a sensitive indicator of bovine mastitis.
Haptoglobin, Bovine, Mammary gland, Immunohistochemistry, mastitis