Colostrum is formed in a pregnant cow about 3-4 weeks before calf delivery. Fluid containing growth factors and other substances are released into the mammary tissue that is currently being developed. Hormones, such as progesterone, regulate this process. The hormones attach to cell receptors which line the mammary gland and prevent the glands from secreting any fluid throughout the pregnancy. About 2 weeks before calf delivery, these hormones assist in the appearance of specific cell receptors which line the mammary gland. These receptors help transfer substances from the pregnant cow's blood into the mammary gland. Some of these substances are necessary antibodies, growth promoters and growth hormones which help in the development of the baby calf.
The hormone balance in the mother cow begins to change about 2 days prior to the birth of the calf. This hormone change initiates secretions and combines substances together. After the baby calf is born and the placenta is delivered, progesterone levels in the mother drop. The blocking of secretions by progesterone is eliminated; a protein-based substance is created in the mammary gland cells and transfers of substances from the mother's blood into the mammary gland are stopped. The fluid in the mother cow found in the mammary gland at birth is called colostrum. It contains high amounts of hormones, metabolically active substances and growth promoters. Colostrum also has a high concentration of protein, is rich in milk fat and low in its lactose content.
After birth, one of the most influential factors on the composition of subsequent secretions is physical removal of the fluid from the mammary gland. The removal of even small quantities of fluid triggers the production of copious amounts of secretion from the cells in the mammary gland. Since the transfer of biologically-active substances from the mother's blood is blocked, replacement fluid will contain primarily substances synthesized by cells in the mammary gland and, thus, will be of a different composition than the fluid originally contained in the mammary gland at birth. The fluid expressed at this time is known as transitional milk. This is further complicated by the fact that the basic composition of the colostrum changes after birth due to maternal reabsorption and does so rapidly beginning at six hours, as can be seen from the table below.10 Thus, the highest quality bovine colostrum, containing the maximum concentration of biologically active substances, is collected in a single milking during the first six hours after parturition.
The rapidly changing composition of colostrum in the mammary gland of the mother fits together very well with events that happen in the body of the newborn calf. During the first six hours of life, the calf's stomach lining does not make any acid and there are very few, if any, enzymes present that can break down ingested proteins. Complete first milking colostrum also contains substances that inhibit the action of some enzymes.
When the calf ingests the first colostrum milking, the enzymes travel through the stomach and intestines without having been broken down. After 6-8 hours after birth, enzymes in the calf's stomach begin to appear in addition to the stomach beginning to acidify. - 31875
The hormone balance in the mother cow begins to change about 2 days prior to the birth of the calf. This hormone change initiates secretions and combines substances together. After the baby calf is born and the placenta is delivered, progesterone levels in the mother drop. The blocking of secretions by progesterone is eliminated; a protein-based substance is created in the mammary gland cells and transfers of substances from the mother's blood into the mammary gland are stopped. The fluid in the mother cow found in the mammary gland at birth is called colostrum. It contains high amounts of hormones, metabolically active substances and growth promoters. Colostrum also has a high concentration of protein, is rich in milk fat and low in its lactose content.
After birth, one of the most influential factors on the composition of subsequent secretions is physical removal of the fluid from the mammary gland. The removal of even small quantities of fluid triggers the production of copious amounts of secretion from the cells in the mammary gland. Since the transfer of biologically-active substances from the mother's blood is blocked, replacement fluid will contain primarily substances synthesized by cells in the mammary gland and, thus, will be of a different composition than the fluid originally contained in the mammary gland at birth. The fluid expressed at this time is known as transitional milk. This is further complicated by the fact that the basic composition of the colostrum changes after birth due to maternal reabsorption and does so rapidly beginning at six hours, as can be seen from the table below.10 Thus, the highest quality bovine colostrum, containing the maximum concentration of biologically active substances, is collected in a single milking during the first six hours after parturition.
The rapidly changing composition of colostrum in the mammary gland of the mother fits together very well with events that happen in the body of the newborn calf. During the first six hours of life, the calf's stomach lining does not make any acid and there are very few, if any, enzymes present that can break down ingested proteins. Complete first milking colostrum also contains substances that inhibit the action of some enzymes.
When the calf ingests the first colostrum milking, the enzymes travel through the stomach and intestines without having been broken down. After 6-8 hours after birth, enzymes in the calf's stomach begin to appear in addition to the stomach beginning to acidify. - 31875
About the Author:
Dr. Anthony Kleinsmith is an expert in colostrum research. Learn more about the colostrum benefits by visiting the colostrum authorities online resources at ImmuneTree.com today!
