Colostrum is the very first milk produced by the mammalian mother and contains high amounts of bioactive factors compared to mature milk from later in lactation. The colostrum is essential for the final development and maturation of the gastrointestinal tract and immune system in the newborn, and is provided during the first few days of life as the majority of the bioactive components reach their maximum concentration within the first 24-48 hours after birth.
General definition and description of colostrum
Milk is the natural diet for all neonate mammals, and the very first milk provided by the mother is called colostrum. This liquid has especially high amounts of bioactive compounds compared to mature milk to give the newborn the best possible start of life. This makes colostrum quite different from mature milk.
At birth, the surroundings around the newborn mammal change from the relatively sterile environment in the mother’s uterus, with a constant nutrient supply via the placenta, to the microbe-rich environment outside with an irregular oral intake of complex milk nutrients through the gastrointestinal tract (Sangild et al., 2013). This transition puts high demands on the gastrointestinal tract of the neonate as this organ plays an important part in both the digestion system and the immune system (Newburg & Walker, 2007).
Colostrum has evolved to care for the highly sensitive mammalian neonates and is believed to contribute signiﬁcantly to initial immunological defense as well as to the growth, development, and maturation of the gastrointestinal tract by providing the neonate with essential nutrients and bioactive factors (Stelwagen et al., 2009; Rathe et al., 2014).
Contents in colostrum
Colostrum consists of several different compounds procduced by either lacteal secretions or derived from the blood serum, which accumulate in the mammary glands during the pregnancy period (Larson et al., 1980). It is only available for the offspring for the first few days of life as the majority of the bioactive components reach their maximum concentration within the first 24-48 hours after birth (Stelwagen et al., 2009). Afterwards, the amounts of proteins and bioactive components decreases rapidly, and the colostrum becomes mature milk (Foley & Otterby, 1978). Thus, it is important the neonate receive sufficient amounts of colostrum as soon as possible after birth (Kehoe et al., 2007).
The key attribute about colostrum is the very high levels of bioactive factors. Some of the most important of these compounds are the immunoglobulins, growth factors, antimicrobial factors, and oligosaccharides. In addition, colostrum also contains the same vitamins, minerals, carbohydrates and proteins as mature milk, just in much higher concentrations (Kelly et al., 2003).
Colostrum for everyone
The composition of colostrum is partly species dependent, as the relative amounts and the molecular structure of some of the contents diverge. However, as many of the most important components are similar, colostrum is not species-specific and can benefit neonates from other species than the producer. One example of this is the feasibility of bovine colostrum as diet supplement for human infants when human colostrum or milk is in limited supply (Jensen et al., 2013).
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Jensen, M. L., Sangild, P. T., Lykke, M., Schmidt, M., Boye, M., Jensen, B. B. & Thymann, T. (2013) Similar efficacy of human banked milk and bovine colostrum to decrease incidence of necrotizing enterocolitis in preterm piglets. The American Journal of Regulatory, Integrative and Comparative Physiology, 305, R4-R12.
Kehoe, S. I., Jayarao, B. M. & Heinrichs, A. J. (2007) A survey of bovine colostrum composition and colostrum management practices on Pennsylvania dairy farms. Journal of Diary Science, 90, 4108-4116.
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Rathe, M., Müller, K., Sangild, P. T. & Husby, S. (2014) Clinical applications of bovine colostrum therapy: a systematic review. Nutrition Reviews, 72(4), 237-254.
Sangild, P. T., Thymann, T., Schmidt, M., Stoll, B., Burrin, D. G. & Buddington, R. K. (2013) Invited review: The preterm pig as a model in pediatric gastroenterology. Journal of Animal Science, 91(10), 4713-4729.
Stelwagen, K., Carpenter, E., Haigh, B., Hodgkinson, A. & Wheeler, T. T. (2009) Immune components of bovine colostrum and milk. Journal of Animal Science, 87 (Suppl. 1), 3-9.