Colostrum is the general name of the milk secreted by mammals within 2-3 days after delivery. Mammalian postpartum hormone levels in the mother will change, the breast began to secrete milk. However, lactation has a gradual change in quality and quantity. Different countries or regions have different distinctions on different periods of milk. Generally, milk within 2-3 days after birth is called colostrum, 4-10 days after birth is called transitional milk, milk from 11 days to 9 months after birth is called mature milk, and milk after 10 months is called late milk. The changes of the quality and quantity of mammalian breast milk just adapt to the digestion and absorption of newborns and the physical needs. ^[1]

The protein content in colostrum is much higher than that in normal milk, especially in whey.Colostrum contains 5 times more protein than normal milk and can be absorbed directly. Especially, colostrum contains more immunoglobulin, lactoferrin, growth factors, macrophages, neutrophils and lymphocytes than normal milk.These substances have the function of preventing infection and enhancing immunity. Colostrum contains a large number of growth factors, especially epithelial growth factors, which can promote the growth of neonatal gastrointestinal epithelial cells, promote the rapid development of liver and other tissues of epithelial cells, and also participate in the regulation of gastric juice pH.The vitamin content in colostrum was significantly higher than that in normal milk. The content of vitamin B2 in colostrum is 3-4 times higher than that in normal milk, and the content of nicotinic acid in colostrum is also higher than that in normal milk.The vitamins A and C in colostrum were 10 times higher than in colostrum, and vitamin D was 3 times higher than in colostrum. Colostrum has high ash content, especially sodium and chlorine content. The content of trace elements such as copper, iron, zinc and other minerals was significantly higher than that of normal milk, and the taste was slightly salty. The iron content of colostrum is 3-5 times of that of normal milk, and the copper content of colostrum is about 6 times of that of normal milk. Especially rich in magnesium salt, can promote gastrointestinal peristalsis, conducive to digestive activities. ^[2]

Human milk contains IgG, IgA and IgM in all stages, but the concentration of these components in Colostrum (milk within 2-4 days after delivery) is the highest. With the prolongation of lactation period, the contents of IgG and IgM decrease significantly.The content of IgA in mature milk (milk from 2 to 9 months after delivery) also decreased significantly.In addition, human milk also contains a variety of antibodies, these antibodies will be distributed in the infant's pharynx, nasopharynx and gastrointestinal mucosa surface, can neutralize toxins, agglutinate pathogens, in order to prevent invasion of the human body.The rich IgG antibody in breast milk plays a role in activating complement and neutralizing many toxins in immune response. IgG antibody has a long duration and is the only antibody that can pass through the placenta to protect the fetus during pregnancy. They also secrete from the mammary gland into colostrum, so that the newborn can get antibody protection at the first time.

The common colostrum products on the market now include bovine colostrum and sheep colostrum,Bovine colostrum research and introduction has been a lot,today I'd like to talk about colostrum. Because with the increasing research and understanding of goat milk, colostrum has gradually come into our view in recent years. However, our understanding of goat colostrum is still partial, and there are few ways to obtain the information of goat colostrum.

The thick and yellow milk produced by female goats within 2-3 days after delivery is called "colostrum".Sheep colostrum has more energy, protein, vitamins and minerals than normal sheep milk due to its unique time effect. What's more important is that sheep colostrum helps the young goats build up the immune system in the first place, so sheep colostrum is rich in IgG.Even more surprising is that human breast milk and colostrum are also rich in IgG, which helps babies improve their immunity as quickly as possible after birth.

The molecular weight of colostrum is small and easy to absorb. The digestibility of goat colostrum for infants and young children is more than 94%, and goat colostrum is the natural dairy product closest to human milk because of its complete nutrition. Small calcium molecules and small lactose molecules in colostrum of sheep can promote the absorption of calcium and help consumers to better grow and develop.^[4]

Goat colostrum is rich in IgG. The laboratory of SKVBL Institute in Europe has detected the content of IgG in goat colostrum and found that every 100g of goat colostrum contains at least 23g IgG. ^[5] In the above contents, it is mentioned that IgG antibody in human breast milk plays a role in activating complement and neutralizing many toxins in immune response. IgG antibody has a long duration and is the only antibody that can pass through the placenta to protect the fetus during pregnancy. They also secrete from the mammary gland into colostrum, so that the newborn can get antibody protection at the first time.

With people's more and more in-depth research and understanding of goat's milk, there are more and more people will study goat colostrum, more stories about colostrum will be presented to you, and our understanding of colostrum will be more and more comprehensive.

[1] Cao Jinsong. Colostrum functional food. China Light Industry Press, 2000

[2].. Lu Dong-lin, Zhang Dan-feng, Jing Wen-qing, et al. Determination of major components and mineral elements in bovine colostrum. CNKI, 2001

[3]. Wang Fengying, Cao Hongwei. Analysis of various factors affecting colostrum secretion. CNKI, 1998

[4] Nalina, Li Feng, Urentuya et al. Dynamic Changes of composition of ewes colostrum. Chinese Dairy Industry, 2009

[5]. Hunan Aze International Trade Co., Ltd. and USKVBL Research Institute Laboratory Jointly Study Sheep colostrum Report, 2018