Colostrum Colostrum Colostrum (known colloquially as beestings, bisnings or first milk) is the first form of milk produced by the mammary glands of mammals (including many humans) immediately following delivery of the newborn. Most species will generate colostrum just prior to giving birth. Colostrum contains antibodies to protect the newborn against disease. In general, protein concentration in colostrum is substantially higher than in milk. Fat concentration is substantially higher in colostrum than in milk in some species, e.g. sheep and horses, but lower in colostrum than in milk in some other species, e.g. camels and humans. In swine, fat concentration of
Mammal the metatherian "Sinodelphys", both dated to 125 million years ago. [[Epipubic]] bones, a feature that strongly influenced the reproduction of most mammal clades, are first found in [[Tritylodontidae]], suggesting that it is a synapomorphy between them and [[mammaliformes]]. They are omnipresent in non-placental mammaliformes, though "[[Megazostrodon]]" and "[[Erythrotherium]]" appear to have lacked them. It has been suggested that the original function of [[lactation]] ([[milk]] production) was to keep eggs moist. Much of the argument is based on monotremes, the egg-laying mammals. Therian mammals took over the medium- to large-sized ecological niches in the [[Cenozoic]], after the [[Cretaceous–Paleogene extinction event]] approximately