Plasma concentrations of bovine pregnancy-associated glycoprotein (bPAG) do not differ during the first 119 days between ongoing pregnancies derived by transfer of in vivo and in vitro produced embryos.

Calves derived from IVP embryos may suffer from the large offspring syndrome that has been related to effects of in vitro culture on the intrinsic quality of the embryo. Limited information is available on the role of the placenta in such cases. In this study, bovine pregnancy-associated glycoprotein (bPAG) was used as a marker to test whether placental function is influenced by the route of embryo production. Therefore, from day 7 until day 119 of ongoing gestations, resulting from transfer of MOET (n = 53), IVP-co-culture (n = 21) and IVP-SOF (n = 38) embryos, bPAG levels were compared in peripheral plasma of recipients. Plasma progesterone levels were compared as well. From day 25 of gestation onwards, bPAG could be detected in all recipients and the levels were significantly influenced by the day of gestation. Although IVP calves were significantly heavier than the in vivo produced calves, this difference was not reflected in the bPAG profiles of the embryo production groups. Yet, the mean bPAG level of the three last sampling moments (days 105-119) tended to be positively related to the birth weight of the calves, irrespective of the embryo production technique. Progesterone concentrations were not influenced by route of embryo production, but were significantly affected by parity of the recipient and day of gestation.