Just like the cow's milk we are accustomed to drink, bovine colostrum and its components are safe for human consumption, except in the context of intolerance or allergy to lactose or other components. Since using human colostrum would raise numerous concerns amongst the public, the production of bovine colostrma s a health supplement is the next best thing.
Bovine colostrum from pasture-fed cows contains immunoglobulins that are non species specific and can work against many human pathogens, including Escherichia coli, Cryptosporidium parvum, Shigella flexneri, Salmonella, Staphylococcus, and rotavirus (which causes diarrhea in infants). This means by consuming bovine colostrum, the immune factors can be passed on and provide pathogen protection in humans.
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.