Relationships of serum estriol, cortisol and albumin concentrations with pig weight at 110 days of gestation and at birth.

In polytocous species, animals with reduced birth weights are associated with reduced neonatal survival, which may be related to substandard placental function. At 110 days of gestation (n = 84) and at birth (approximately 114 days, n = 193), fetal pigs were bled and weighed, so that indexes of placental function (estriol), fetal stress (cortisol), and fetal growth (albumin) could be related to fetal development. Concentration of estriol at birth or 110 days of gestation was not linearly related to weight of pig. Pig serum albumin was linearly related to pig weight and increased as body weight increased (p less than 0.05). In blood from pigs sampled at birth, cortisol concentrations significantly decreased as body weight increased (p less than 0.05).