Offspring derived from artificial reproductive techniques are already known to present several postnatal undesirable phenotypes and clinical disorders. Despite its benefits, cloning by somatic cell nuclear transfer (SCNT) is extremely inefficient. The birth rate in cattle is around 5% of the transferred blastocysts, and ~50% of delivered calves die in the first 48 h. Neonatal respiratory distress is reported to be one of the main causes of such deaths. Veterinary intervention is often needed to promote or improve blood oxygenation, avoiding respiratory acidosis and improving carbon dioxide delivery from blood/lungs to the environment. This study aimed to evaluate a neonatal support therapy over the blood gas and acid-base balance on newborn calves derived from SCNT or AI. Four cloned and 3 AI-derived calves delivered by Caesarean section were used for the experiment. Postnatal therapeutic procedures were comprised 4 doses of 400 mg of intratracheal surfactant every 15 min, 25 mg of oral sildenafil every 8 h for 3 days, and 5 L min–1 intranasal oxygen. Blood collections were performed within 30 min (T0), at 12 (T12), 24 (T24) and 48 (T48) hours after delivery. Blood samples were collected from the caudal auricular artery with a butterfly and a blood gas syringe. Oxygen saturation (sO2), arterial pressure of oxygen (PaO2) and carbon dioxide (PaCO2), pH, and bicarbonate (HCO3–) were evaluated with a portable blood gas analyzer (i-STAT, Abbott Point of Care Inc., Princeton, NJ, USA). Data obtained were submitted to ANOVA (Proc MIXED; SAS/STAT, version 9; SAS Institute Inc., Cary, NC, USA). There were significant differences between groups in blood pH (P = 0.0182) and between groups (P = 0.0281) and time of collection (P = 0.0303) in blood bicarbonate (HCO3–). The AI calves were born with normal pH (7.468 ± 0.033) and the cloned calves were born in acidosis (7.216 ± 0.166). These calves were stabilised in T48 (7.427 ± 0.017) using their own HCO3– that increased over time. Although there were no differences in sO2 (P = 0.4525), PaO2 (P = 0.3086), or PaCO2 (P = 0.2514), sO2 and PaO2 were numerically increased at the same time that PaCO2 decreased in both groups. In the cloned calves, the sO2, PaO2, and PaCO2 at T0 were 61.3 ± 28.6%, 39.8 ± 18.5 mmHg, and 65.8 ± 29.3 mmHg, respectively and reached 90.0 ± 3.4%, 57.7 ± 15.8 mmHg, and 42.0 ± 3.7 mmHg. In the AI calves, T0 blood gas analysis were 79.8 ± 19.4%, 56.1 ± 42.1 mmHg, and 39.1 ± 4.8 mmHg, and at T48 were 89.0 ± 2.6%, 82.3 ± 43.5 mmHg, and 43.0 ± 4.9 mmHg for sO2, PaO2, and PaCO2 respectively. The neonate support therapy improved calves' oxygenation and helped to eliminate the carbon dioxide from the blood. In our experience, the neonatal treatment was essential in supporting the lives of the cloned calves.Funding support was received from FAPESP 2011/19543–9.
Why hemolysis detection should be an integral part of any near-patient blood gas analysis
