That is true, but so misleading that you have to get the full story here. ONLY a small part of the colostrum is actually helpful to the immune system. THAT part is called the transfer factor. It is extracted by a special process from the colostrum. Since there is a patent which greatly limits anyone's ability perform this extraction, many companies without access to that patent have started claiming immune-system building values to the colostrum itself.
Transfer factors are less than one part in a thousand of colostrum.
Colostrum is mother's milk during the first few days of breastfeeding. That is a dangerous lie. Babies are at risk without breast fed milk to transfer of immunity from the mother. This is a massive source of technical information about a substance which is starting to revolutionize health care.