It is higher in protein and vitamin A than milk. Colostrum contains immunoglobulins to provide passive immunity to neonate until its own immune system begins to function. B. True Milk 1. C. Other substances 1. Cortisol, thyroid hormones, insulin, GH synergize with estrogen and progesterone during pregnancy to increase mammary development.
Prolactin is necessary for the start of lactation.
In cows after lactation starts prolactin is no longer necessary. GH can increase milk production in cows by directing nutrient transfer to the mammary gland. Prolactin will not cause this effect. This effect of GH reduces the amount of nutrients available for other physiological systems. V. Milk removal A. Suckling and or removal of milk are necessary for continued lactation.