Colostrum effects on the gastrointestinal tract, and on nutritional, endocrine and metabolic parameters in neonatal calves

Newborn calves are characterised by marked cardio-respiratory, metabolic an d endocrine changes which continue during ensuing weeks and months. Thus, a lthough the somatotrophic axis is basically functioning in neonatal calves, it is not yet mature. The speed of the adaptations of the various traits d iffers widely. The ability to digest colostrum and milli requires specific structures and functions of the gastrointestinal tract. Colostrum compositi on exhibits major changes after the onset of lactation, Colostrum intake is important for passive immunity, but also for the provision of carbohydrate s, lipids, proteins, minerals and vitamins. In addition, colostrum contains hormones, growth factors, cytokines, enzymes, polyamines and nucleotides, which in the neonatal calf can exert biological effects. Thus, insulin-like growth factor I, which in colostrum is present in high amounts, may enhanc e gastrointestinal tract development and function of neonatal calves. Colos trum should be ingested as soon as possible after birth for efficient and s ufficient absorption not only of immunoglobulins, but apparently also of (e ssential and non-essential) fatty acids and fat-soluble vitamins (beta-caro tene, retinol and alpha-tocopherol). The pattern of essential amino acids a nd the glutamine/glutamate ratio in blood plasma also greatly depend on whe ther and when colostrum is fed. In addition, there are considerable effects on hormones (especially on concentrations of insulin, glucagon, insulin-li ke growth factor-I, including its binding proteins, and cortisol) that are dependent on time and amount of colostrum fed. (C) 2000 Elsevier Science B. V. All rights reserved.