Lactation Biology Symposium: the long-term impact of epigenetics and maternal influence on the neonate through milk-borne factors and nutrient status.

Mammalians undergo dramatic organ-specific as well as metabolic and endocrine changes after birth. Nutrient intake shifts from continuous glucose supply via the placenta to discontinuous colostrum and milk intake with lactose and fat as main energy sources. The development of the neonatal calf is influenced by colostrum intake when compared with colostrum replacement diets. Besides establishing a passive immunity, colostrum promotes maturation and function of the neonatal gastrointestinal tract (GIT) in calves. Nutrients and non-nutritive factors, such as hormones and growth factors, which are present in high amounts in colostrum of first milking, affect intestinal growth and function and enhance the absorptive capacity of the GIT. In addition, colostrum feeding improves the glucose status in neonatal calves. Glucose absorption increases and glycogen concentrations in liver rise much higher when colostrum instead of a milk-based colostrum replacer is fed. In contrast, first-pass glucose uptake in the splanchnic tissue is greater in calves fed colostrum replacer without growth promoting substances. The improved energy status in neonatal calves after enhanced colostrum intake leads to accelerated stimulation of anabolic processes indicated by an enhanced maturation of the postnatal somatotropic axis and increased production of endogenous IGF-I in neonatal calves. Besides the somatotropic axis, other endocrine changes such as higher postprandial insulin release, a reduced glucagon to insulin ratio and cortisol level in blood plasma, and an increased plasma leptin concentration after colostrum instead of replacer feeding support the concept of stimulation of anabolic processes. These endocrine changes may favor postnatal organ development and may improve growth and lactation performance in cattle in later life. Therefore, intensive colostrum and subsequent milk feeding by increasing amounts and frequency of colostrum and milk intake may have long-lasting effects on postnatal performances and might be a key factor of successful cattle breeding.