Maternal environment and embryo origin effects on placental function, offspring vigor, growth, and reproductive parameters

Abstract

Maternal nutrition and the use of assisted reproductive technologies have previously been reported to impact placental function, nutrient transfer, calf growth and vigor, and offspring reproductive parameters. It is important to describe these effects as they may uncover new targets for improving embryonic and fetal development and pregnancy retention in livestock species. The overreaching goal of this work was to determine how maternal nutrition and embryo origin affects offspring growth through weaning, neonate vigor, and reproductive parameters. For study 1) we hypothesized that maternal injectable mineral administration during mid and late gestation will improve calf growth through weaning and offspring reproductive parameters. Lastly, in study 2) we hypothesized that embryo origin would alter placental hormone production consequently impacting placental morphology, calf vigor and growth through weaning. Study 1) A total of 278 cows were enrolled in the study, blocked by body weight, parity, and day of gestation, and then randomly assigned to one of two groups: 1) a group that received an injectable mineral (MM = 138) or control group (CON = 138) which did not receive injectable mineral. Adjusted birth weight and weaning weights were recorded. Calves whose dams received the mineral injection were heavier at birth compared to the control (P = 0.05). Study 2) Cows carrying an artificial insemination derived pregnancy (AI = 23), natural service derived pregnancy (NS = 23), or in- vitro produced embryo (IVP = 23) were randomly selected for placental collection and calf vigor and growth assessments. A group by calf sex interaction was observed for calf birth weight, time between birth and nursing (minutes), and time between standing and nursing (minutes; P < or = 0.05). Overall, the method by which embryo was produced, or the intrauterine environment can positively, negatively, or have no impact on the postnatal growth and development of the offspring.