Human reproductive ecology to aid infant survival and growth. Lactational strategies vary cross-culturally, but can typically be defined by sibling sets and sex ratios, frequency of nursing, entire lactational duration, and milk composition. Milk is composed of my bioconstituents, but only a few will be outlined here. In the first days of puerperium, the first milk is thick and yellowish, also called colostrum. For weeks after that, mature milk is expressed and it has been shown that fetal-mammary gland signaling occurs even before birth in determining milk type and concentrations based on the fetus sex. Colostrum plays an important role in establishing the
Colostrum on adult gut health in several recent well controlled published studies. Evidence for the beneficial effect of colostrum on extra-gastrointestinal problems is less well developed, due in part to the limited number of randomised double-blind studies published, although a variety of possible uses have been suggested. Dairy cattle are naturally exposed to pathogens and produce immunoglobulins against them. These antibodies are present in the cow’s bloodstream and in the colostrum. These immunoglobulins are specific to many human pathogens, including "Escherichia coli, Cryptosporidium parvum, Shigella flexneri, Salmonella "species", Staphylococcus" species, and rotavirus (which causes diarrhea in infants). Before the development of