Blood Glucose and Fructose in the Newborn Ruminant

Abstract

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 3min after birth and at 30min intervals until calves were 6h of age and then at 1h intervals until 24h of age. Calves were fed 1kg of their dam's colostrum at 6, 12, and 18h of age. Rectal temperatures were recorded at the same intervals as blood samples were taken. Jugular blood samples were taken from lambs within 3min after birth and at 2, 4, 6, 8, and 24h 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/100ml in calves at birth while lambs had 13 mg/100ml glucose and 46 mg/100ml 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 colostrum. Body temperature remained normal throughout the 24h. Lambs exhibited low blood glucose through the first 24h of life. Blood fructose concentrations in lambs were similar to those of calves. Newborn neonatal ruminants may not be dependent upon glucose as their principle energy substrate during the first 24h of life.