Immunoglobulin is a fancy term for one of the many different parts of the immune system, fighting bacteria, parasites, viruses, germs, fungus and other assorted bad characters. When your body is healthy your immune system should handle any antibody without need of antibiotics. Colostrum is mother's milk during the first few days of breastfeeding. That is a dangerous lie. Once you have these transfer factors in your body, your body then manufacturers immunoglobulins.
Babies are at risk without an immunoglobulin to fight the germs that invade.
It turns out, that people who are often sick, have an antibody which the immune system couldn't recognize. You may need what is contained within colostrum to fight every antibody you ever have invade your body. You will have plenty of immunoglobulins then.