Effect of the level of asphyxia during delivery on viability at birth and early postnatal vitality of newborn pigs

Newborn pigs (n = 117) were used to provide information on the relationships of degree of asphyxia during delivery, viability at birth, and some striking aspects of postnatal vitality including survival, interval between birth and first udder contact and between birth and first suckling, rectal temperature at 24 h of life ([RT.sub.24]), and growth rate over the first 10 d of life. The degree of asphyxia at birth was estimated from cord blood pC[O.sub.2], pH, and lactate levels. Onset of respiration, heart rate, skin color, and attempts to stand during the first minute after birth were used to estimate the viability score. Neonatal asphyxia, i.e., decreased blood pH and increased blood pC[O.sub.2] and lactate, was associated with the production of unusually high levels of catecholamines. The degree of asphyxia increased with late position in the birth order (P < .01) and was higher in piglets born posteriorly (P < .05). Further, the average blood pC[O.sub.2] within a litter increased (P < .05) with litter size. There was an inverse relationship between the degree of asphyxia and the viability score (P < .001). Highly viable piglets reached the udder more rapidly (P < .001) and had a higher [RT.sub.24] (P < .001) than those of low viability. Plasma glucose concentrations increased with blood pC[O.sub.2] and plasma epinephrine concentrations (P < .001). Neonatal asphyxia reduced postnatal vitality by delaying the first contact with the udder (P < .03) and was associated with a lower [RT.sub.24] (P < .05), growth rate (P < .001), and survival over 10 d (P < 0.06). These variables, i.e., interval between birth and first udder contact, [RT.sub.24], and growth rate, were correlated with birth weight (P < .001); [RT.sub.24] was also shown to decrease (P < .001) with the time taken to reach the udder. Overall, results suggest that piglets suffering from asphyxia during delivery are less viable at birth and less prone to adapt to extra-uterine life. Key Words: Asphyxia, Parturition, Piglets, Viability, Postnatal Vitality