Colostrum milk at 48 to 72 hours after parturition may be higher than in colostrum or in late-lactation milk. Fat concentration in bovine colostrum is extremely variable. Newborns have very immature and small digestive systems, and colostrum delivers its nutrients in a very concentrated low-volume form. It has a mild laxative effect, encouraging the passing of the baby's first stool, which is called meconium. This clears excess bilirubin, a waste-product of dead red blood cells, which is produced in large quantities at birth due to blood volume reduction from the infant's body and helps prevent jaundice. Colostrum is known to contain
Colostrum bottle. Although many claims of health benefits have been made for colostrum consumption in adults, until recently there have been limited randomized trials to support these assertions. It is probable that little absorption of intact growth factors and antibodies into the bloodstream occurs, due to digestion in the gastrointestinal tract. However, the presence of casein and other buffering proteins does allow growth factors and other bioactive molecules to pass into the lumen of the small intestine intact, where they can stimulate repair and inhibit microbes, working via local effects. This provides a probable mechanism explaining the positive results of colostrum