Colostrum
Colostrum is the first form of milk produced by the mammary glands of mammals 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 milk at 48 to 72 hours postpartum 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 immune cells and many antibodies such as IgA, IgG, and IgM. These are some of the components of the adaptive immune system. In preterm infants some IgA may be absorbed through the intestinal epithelium and enter the blood stream though there is very little uptake in full term babies. This is due to the early "closure" of the intestinal epithelium to large molecule uptake in humans unlike the case in cattle which continue to uptake immunoglobulin from milk shortly after birth. Other immune components of colostrum include the major components of the innate immune system, such as lactoferrin, lysozyme, lactoperoxidase, complement, and proline-rich polypeptides. A number of cytokines are found in colostrum as well, including interleukins, tumor necrosis factor, chemokines, and others. Colostrum also contains a number of growth factors, such as insulin-like growth factors I, and II, transforming growth factors alpha, beta 1 and beta 2, fibroblast growth factors, epidermal growth factor, granulocyte-macrophage-stimulating growth factor, platelet-derived growth factor, vascular endothelial growth factor, and colony-stimulating factor-1.
Notably in humans a lack of colostrum production is linked to a mutation in the ABCC11 gene that occurs in most people of East Asian descent. This gene is also one of the determining factors in wet or dry type earwax, as the mammary glands are a form of apocrine gland.
In animal husbandry
Colostrum is crucial for newborn farm animals. They receive no passive transfer of immunity via the placenta before birth, so any antibodies that they need have to be ingested. The ingested antibodies are absorbed from the intestine of the neonate. The newborn animal must receive colostrum within 6 hours of being born for maximal absorption of colostral antibodies to occur. Recent studies indicate that colostrum should be fed to bovines within the first thirty minutes to maximize IgG absorption rates.Colostrum varies in quality and quantity. In the dairy industry, the quality of colostrum is measured as the amount of IgG per liter. It is recommended that newborn calves receive at least 4 quarts of colostrum with each containing at least 50 grams of IgG/liter. Testing of colostral quality can be done by multitude of devices including colostrometer, optical refractometer or digital refractometer. Mature dairy cattle produce an average of 33 liters of colostrum in the first milking after calving.
Livestock breeders commonly bank colostrum from their animals. Colostrum can be stored frozen but it does lose some of its inherent quality. 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 pathogens occurring on the premises. A German study reported that multiparous mares produced on average a liter of colostrum containing 70 grams of IgG.
In most dairy cow herds, the calves are separated from their mothers soon after birth and fed colostrum from a bottle.
Human consumption of bovine colostrum
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 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. Before the development of antibiotics, colostrum was the main source of immunoglobulins used to fight bacteria. In fact, when Albert Sabin made his first oral vaccine against polio, the immunoglobulin he used came from bovine colostrum. 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.
The gut plays several important roles including acting as the main pathway for fluid, electrolyte and nutrient absorption while also acting as a barrier to toxic agents present in the gut lumen including acid, digestive enzymes and gut bacteria. It is also a major immunological defence mechanism, detecting natural commensals and triggering immune response when toxic microbes are present. Failure of homeostasis due to trauma, drugs and infectious microbes not only damages the gut but can lead to influx of damaging agents into the bloodstream. These mechanisms have relevance for multiple conditions affecting all areas of the world and socioeconomic groups such as ulcers, inflammation, and infectious diarrhea. There is currently much interest in the potential value of colostrum for the prevention and treatment of these conditions as it is derived from natural sources and can influence damaging factors through multiple pathways including nutritional support, immunological intervention and growth/healing factor constituents. As pointed out by Kelly, inconsistency between results in some published studies may be due in part to variation in dose given and to the timing of the colostrum collection being tested.
Some athletes have used colostrum in an attempt to improve their performance, decrease recovery time, and prevent sickness during peak performance levels. Supplementation with bovine colostrum, 20 grams per day, in combination with exercise training for 8 wk may increase bone-free lean body mass in active men and women.
Low IGF-1 levels may be associated with dementia in the very elderly, although causation has not been established. Malnutrition can cause low levels of IGF-1, as can obesity. Supplementation with colostrum, which is rich in IGF-1, can be a useful part of a weight reduction program. Although IGF-1 is not absorbed intact by the body, some studies suggest it stimulates the production of IGF-1 when taken as a supplement whereas others do not
Colostrum also has antioxidant components, such as lactoferrin and hemopexin, which binds free heme in the body.
The Isle of Man had a local delicacy called "Groosniuys", a pudding made with colostrum.
A sweet cheese like delicacy is made with colostrum in south Indian states of Andhra Pradesh, Telangana called 'Junnu'. This is made with the milk of buffalo as well as cow. the milk produced by Cow or a buffalo on the 2 day of giving birth is considered to be the best for making this pudding like delicacy. The colostrum has a very high demand in these states which has resulted in adulteration too.