More info on Colostrum from Wikipedia.org. It appears to stimulate growth of the gut, helps probiotics establish a home in the gut. Fascinating that the first polio vaccine used bovine colostrum instead of antibiotics.

“PRP” = Proline-rich Polypeptides.

PRP rich preparations of bovine colostrum appear to act as an immune regulator, helping the immune system to respond appropriately to pathogens.

Amplify’d from en.wikipedia.org
Colostrum (also known colloquially as beestings,[1] bisnings[2] or first milk) is a form of milk produced by the mammary glands of mammals in late pregnancy. Most species will generate colostrum just prior to giving birth. Colostrum contains antibodies to protect the newborn against disease, as well as being higher in fat and protein than ordinary milk.
A number of cytokines (small messenger peptides that control the functioning of the immune system) are found in colostrum as well,[8] including interleukins,[8] tumor necrosis factor,[9] chemokines,[10] and others. Colostrum also contains a number of growth factors, such as insulin-like growth factors I,[11] and II,[12] transforming growth factors alpha,[13] beta 1 and beta 2,[14][15] fibroblast growth factors,[16] epidermal growth factor,[17] granulocyte-macrophage-stimulating growth factor,[18] platelet-derived growth factor,[18] vascular endothelial growth factor,[19] and colony-stimulating factor-1.[20]
The most pertinent bioactive components in colostrum are growth factors and antimicrobial factors. The antibodies in colostrum provide passive immunity, while growth factors stimulate the development of the gut.
Livestock breeders commonly bank colostrum from their animals. Colostrum produced on a breeder’s own premises is considered to be superior to colostrum from other sources, because it is produced by animals already exposed to (and, thus, making antibodies to) pathogens occurring on the premises.

Assertions that colostrum consumption is of human benefit are questionable because most ingredients undergo digestion in the adult stomach, including antibodies and all other proteins.[citation needed]

Bovine colostrum and its components are safe for human consumption, except in the context of intolerance or allergy to lactose or other components. It shows promise in the treatment or prevention of a variety of disease states.[23][24][25]

Before the development of antibiotics, colostrum was the main source of immunoglobulins used to fight infections. In fact, when Albert Sabin made his first oral vaccine against polio, the immunoglobulin he used came from bovine colostrum.[27] When antibiotics began to appear, interest in colostrum waned, but, now that antibiotic-resistant strains of pathogens have developed, interest is once again returning to natural alternatives to antibiotics, namely, colostrum.[28]
A single study showed protective effects against influenza, 3 times greater than that of vaccination.[29]

Some athletes have used colostrum in an attempt to improve their performance,[30] decrease recovery time,[31] and prevent sickness during peak performance levels.[32] Using colostrum supplementation, the Australian Olympic swim team won more gold medals than China in the 2000 and 2004 Olympic games.[33] Research fails to show a conclusive effect of colostrum on lean body mass.[30][34]

PRP-rich preparations from bovine colostrum have shown some activity against various diseases including viral infections[47] of herpes viruses[48] and HIV,[49] as well as difficult to treat bacterial and fungal infections like Mycobacterium fortuitum[50] and Mycobacterium tuberculosis[51] (cause of tuberculosis), cryptosporidosis in AIDS patients,[52] and candida.[53] Also for various forms of cancer, such as Hodgkin’s disease,[54] osteogenic sarcoma,[55] prostate cancer,[56] and others.
As an immune modulator, PRP is also effective in disease states characterized by an overactive immune system, such as allergies,[57][58] asthma,[59] and autoimmune diseases.[60]
PRP has some effect in neurodegenerative diseases, especially Alzheimer’s disease,[61] but has not yet shown longterm disease retarding effect.[62]
There is one report of use in patients with intractable epilepsy.[64]
Proline-rich Polypeptides (PRP)
These small immune signaling peptides were independently discovered in colostrum and other sources, such as blood plasma, in the United States,[42] and Poland[43].Read more at en.wikipedia.org