ABSTRACT:The objective of this review is to integrate clinical findings and laboratory analyses in such a way to improve the welfare of newborn piglets and achieve better prognoses of neonatal viability. Deaths during the intrapartum period account for a significant proportion of pre-weaning mortality in farms worldwide. Piglets which die during parturition generally have normal size and typically lack gross lesions at post-mortem examination. However, circulatory abnormalities in the umbilical cord help in assessing piglet viability. Cord lesions can be classified as normal (adhered), oedematous, congested or haemorrhagic and should always be evaluated in perinatal deaths. The likelihood of neonatal survival decreases rapidly as the severity of umbilical cord lesions increase. The physiometabolic blood profile which includes acid-base balance, degree of dehydration, mineral balance, metabolic expenditure and gas exchange are also useful clinical elements for properly assessing neonatal viability. Neonatal survival is notably reduced when the blood pH falls below 7.0, lactate rises above 90 mg/dl, bicarbonate drops below 10 mmol/l, or the pCO 2 increases above 110 mm/Hg. Blood calcium is also an excellent indicator of neonatal stress when used in combination with the other parameters mentioned above. Trembling due to an imbalance in the movement of calcium in muscle is also a factor involved in neonatal mortality. Neurological function in the newborn piglet could also be evaluated by adapting the Apgar score widely used in human perinatology. Neonates with scores lower than 6 in a 10 point scale have generally lower survival rates. The two most important indicators for this vitality score are breathing latency and bradycardia. If the neonate has apnoea for more than 5 min and the cardiac frequency does not increase to more than 110 beats per minute the prognosis for survival is rather poor.

ABSTRACT:The aim of this review was to elaborate a conceptual framework of the most important aspects of the main biochemical processes of synthesis and breakdown of energy substrates that human and pig foetuses and newborns can use during the transition from foetus to newborn. Under normal physiological conditions, the growth and development of the foetus depends upon nutrients such as glucose, lipids and amino acids. In addition to the maternal and foetal status, genetic factors are also reported to play a role. The main function of the placenta in all species is to promote the selective transport of nutrients and waste products between mother and foetus. This transport is facilitated by the close proximity of the maternal and foetal vascular systems in the placenta. The foetus depends on the placental supply of nutrients, which regulates energy reserves by means of glycogen storage. Also, the synthesis of foetal hepatic glycogen guarantees energy reserves during perinatal asphyxia or maternal hypoglycaemia. However, the foetus can also obtain energy from other resources, such as gluconeogenesis from the intermediary metabolism of the Krebs cycle and most amino acids. Later, when the placental glucose contribution ends during the transition to the postnatal period, the maturation of biological systems and essential metabolic adaptations for survival and growth is required. The maintenance of normoglycaemia depends on the conditions that determine nutrient status throughout life: the adequacy of glycogen stores, the maturation of the glycogenolytic and gluconeogenic pathway, and an integrated endocrine response.

Piglets appear to be neurologically sensitive to intrapartum asphyxia. Our aim was to investigate the short-term neurophysiologic consequences of intrapartum asphyxia in piglets. We studied 10 piglets suffering intrapartum asphyxia and 10 control piglets. Glucose and blood gas levels, tympanic membrane temperature, and body weight were measured within the first 2 min after birth. Animals were followed up for a 5-day period. As surrogated markers of piglets' neurological function, a viability score and the time elapsed from birth to the first contact with the maternal udder were recorded. In the control group, temperature and blood pH levels at birth were significantly higher (p < or = .001), whereas calcium, lactate and PCO2 levels were statistically lower (p < or = .05) than in the piglets experiencing intrapartum asphyxia. Lower temperature and blood pH levels as well as higher blood PCO2 and lactate levels were observed in piglets with lower viability scores and in piglets with prolonged times until first udder contact. At the end of the study, asphyxiated piglets weighed on average 200 g less (p = .023) than control piglets. In conclusion, intrapartum asphyxia in spontaneously born piglets was associated with signs of acute neurological dysfunction and lower weight gain, supporting the hypothesis that they may be used as a naturalistic model for the study of asphyxia in newborns.

The objective of this study was to evaluate uterine activity at farrowing in sows with different gestation lengths (GL), and its effect on the metabolic profile, blood gases and daily weight gain of neonate piglets. The experiment covered a period of 25 weeks and involved 200 Yorkshire-Landrace sows. The animals were assigned to four groups of 50 sows each and distributed according to GL, as follows: GL1: 107–109 days; GL2: 110–113 days; GL3: 114–116 days; GL4: 117–119 days. The productive indicators of the sows were recorded, as were the survival outcomes of the neonatal pigs. Fetal cardiac frequency and both intensity and frequency of myometrial contractions were monitored using a Corometrics Fetal monitor. The blood gases, electrolytes and glucose levels of the neonates were obtained by means of an automatic blood gas and electrolyte analyser. The GL groups GL1 and GL2 had more prolonged births (>226.26 ± 4.95 min) regardless of litter size (P < 0.05). Of the four groups, GL1 presented the longest duration (P < 0.05) of the expulsion phase (P < 0.05), the highest number of uterine contractions (P < 0.05), and the highest and lowest number of intra-partum deaths (P < 0.05) and live births, respectively. The live birth piglets in this group had both the lowest birthweights (P < 0.05) and the highest incidences of hypercapnia, hyperlactatemia and hypercalcaemia (P < 0.05), which later resulted in lower rates of daily weight gain (P < 0.05). In conclusion, premature births increase the number of intra-partum deaths and result in lower birthweights, the presence of apnoea, and severe metabolic alterations in piglets.

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