) First Defense Technology Gel Tubes provide specific globulin proteins to help strengthen the immune system of newborn calves. Highly concentrated and easily absorbed for immediate intestinal support and safeguard against disease. Derived from natural bovine colostrum. Ready-to-use gel is blue to ensure and trace proper dosage. Feed 1 gel tube per calf as soon as possible after birth. First Defense Technology Gel Tubes are recommended for use in conjunction with a quality colostrum feeding program. Do not use with a modified live vaccine at birth, as the antibodies in First Defense will neutralize the vaccine.