Ease of calving, blood chemistry, insulin and bovine growth hormone of newborn calves derived from embryos produced in vitro in culture systems with serum and co-culture or with PVA

Blood chemistry (pH, pCO(2), pO(2), glucose, lactate) as well as plasma ins ulin and growth hormone of calves derived from embryos produced under 2 dif ferent in vitro culture systems (modified SOFaa with 20% serum and co-cultu re with bovine oviduct epithelial cells [IVPserum, n=8] or with 3 mg/mL. PV A [IVPdefined, n=6]) were compared with those of calves derived from AI (n= 5). Calvings were classified according to the ease (unassisted, light tract ion, heavy traction). Blood samples were taken from the jugular vein of cal ves at 5, 15, 30 and 60 min, and at 2, 3, 6, 12, 18 and 24 h after delivery , then daily for 6 d. At the second day of life after 4 feedings and a 4-h fasting period, a glucose tolerance test was performed to evaluate glucose metabolism and insulin secretion. Calves in the IVPserum group had higher b irth weights than AI calves (LSmeans +/- SEM, IVPserum: 45.2 +/- 1.4 kg vs AI: 40.4 +/- 1.7 kg; P < 0.05), while the birth weights of calves in the IV Pdefined group were in between (IVPdefined: 41.9 +/- 1.6 kg). More IVPserum calves (75%) needed assistance than IVPdefined (33%) or AI (40%) calves. T he effect of ease of calving vs the effect of embryo culture was compared i n relation to blood parameters at birth. There was an effect of ease of cal ving but not of embryo culture conditions on blood pH, lactate and PCO2. Ca lves requiring heavy traction had lower pH during the first 3 h after calvi ng, a higher lactate during the first 60 min after calving and a higher pCO (2) the first 2 h after calving than calves born unassisted. Calves requiri ng heavy traction also had lower pH the first 2 h and higher lactate the fi rst 3 h after calving than calves born by light traction. IVPdefined calves had lower lactate than IVPserum calves the first 60 min after calving. At 6 h after delivery, all blood parameters had stabilized. There was no effec t of either embryo culture or ease of calving on basal insulin and growth h ormone level, or the ability of the calves to handle glucose postnatally an d during a glucose tolerance test. (C) 2000 by Elsevier Science Inc.