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

Abstract

Blood chemistry (pH, pCO 2, pO 2, glucose, lactate) as well as plasma insulin and growth hormone of calves derived from embryos produced under 2 different in vitro culture systems (modified SOFaa with 20% serum and co-culture with bovine oviduct epithelial cells [IVPserum, n=8]or with 3 mg/mL PVA [IVPdefined, n=6]) were compared with those of calves derived from AI (n=5). Calvings were classified according to the ease (unassisted, light traction, heavy traction). Blood samples were taken from the jugular vein of calves 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 birth 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 IVPdefmed group were in between (IVPdefined: 41.9 ± 1.6 kg). More IVPserum calves (75%) needed assistance than IVPdefined (33%) or AI (40%) calves. The effect of ease of calving vs the effect of embryo culture was compared in relation to blood parameters at birth. There was an effect of ease of calving but not of embryo culture conditions on blood pH, lactate and PCO 2. Calves requiring heavy traction had lower pH during the first 3 h after calving, a higher lactate during the first 60 min after calving and a higher pCU 2 the first 2 h after calving than calves born unassisted. Calves requiring heavy traction also had lower pH the first 2 h and higher lactate the first 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 effect of either embryo culture or ease of calving on basal insulin and growth hormone level, or the ability of the calves to handle glucose postnatally and during a glucose tolerance test.