Abstract
Milk trypsin-inhibitor levels were followed during clinical and experimental endotoxin-induced mastitis. Milk trypsin-inhibitor level proved to be a good indicator of mastitis, closely relating to milk BSA values. The trypsin-inhibitor pattern in the quarter milk samples during mastitis closely resembled the pattern of BSA, which indicates that the trypsin-inhibitor is blood derived and diffuses to the mammary gland lite albumin. The timing of the increase in the trypsin-inhibitor into the endotoxin infused quarter closely matched with the increase in body temperature, heart rate, decrease in blood leucocytes and increase in somatic cells. Serum zinc and iron showed a decrease a few hours later.