Plasma metabolite and hormone concentrations in Friesian calves differing in genetic potential for milkfat production

Abstract

Abstract The effects of fasting, feeding, and an arginine infusion on plasma concentrations of glucose, insulin, and growth hormone (GH) were examined in 39 milk-fed Friesian calves born to either high breeding index (HBI) or low breeding index (LBI) parents. In Trial 1, 13 male and 11 female calves were used when they were 8 – 18 days old. Glucose and insulin concentrations in plasma were consistently higher in the HBI group than in the LBI group. Differences in glucose concentration between the BI groups were significant (P < 0.05) following an overnight fast. Differences in insulin concentration were significant both after the overnight fast and after feeding. GH concentrations were generally higher in HBI than LBI calves and the difference was significant (P < 0.05) following arginine infusion. In Trial 2, eight HBI and seven LBI bull calves were bled at 18 – 26 days old for 3 consecutive days. It was again observed that glucose concentrations were significantly higher in the HBI calves than in the LB...