Blood Glucose and Fructose in the Newborn Ruminant

Concentrations of blood glucose and fructose were studied in 8 calves and 20 lambs.Calves were removed from their dams immediately following birth.Jugular blood samples were taken 3 min after birth and at 30 min intervals until calves were 6 h of age and then at 1 h intervals until 24 h of age.Calves were fed 1 kg of their dam's eolostrttm at 6, 12, and 18 h of age.Rectal temperatures were recorded at the same intervals as blood samples were taken.Jugular blood samples were taken from lambs within 3 min after birth and at 2, 4, 6, 8, and 24 h of age.Lambs were allowed to nurse their dams after the initial blood sample.Blood glucose averaged 62 mg/100 ml and fructose 52 mg/100 ml in calves at birth while lambs had 13 mg/100 ml glucose and 46 rag/100 ml fructose at birth.Blood glucose and fructose decreased rapidly during the first few hours of life in calves.Feeding colostrum to calves did not give a uniform rise in blood glucose.Peak blood glucose occurred after the second feeding of eolostrum.Body temperature remained normal throughout the 24 b.Lambs exhibited low blood glucose through the first 24 h of life.Blood fructose concentrations in lambs were similar to those of calves.NewIcon~ neonatal rtun:nants may not be dependent upon glucose as their principle energy substrate during the first 24 h of life.