Developmental programming of the neonatal period in ruminant livestock: a review

Early life, or the neonatal period, is perhaps the most challenging time for ruminant livestock, as they adapt to the extra-uterine environment, undergo important physiological maturation, and navigate harsh ambient conditions. Maternal influences during gestation, especially energy and protein nutrition in late pregnancy, can alter many processes that affect the neonatal period. These processes include fetal growth and development, gestation length, difficulty of parturition, and maternal behavior, which interact to affect offspring vigor at birth. Moreover, colostrum and early milk production and composition are affected by gestational nutrition, and these along with the previous factors affect the neonate's ability to obtain transfer of passive immunity, thermoregulate, perform basal metabolism, and ultimately survive to weaning. Often, the long-term effects of maternal nutrition during gestation on offspring are attributed solely to the prenatal environment, but it is critical to also consider influences of early life on later productivity and health. More research is needed to integrate these neonatal outcomes with prenatal and postnatal mechanisms as well as later ruminant livestock performance. Better understanding of the maternal environment's effects on the neonatal period provides opportunity for improved management of ruminant livestock dams and offspring.