Hormone Responses to Glucose Injection in Japanese Black Cattle and Holstein Cattle

Abstract

We compared the change in the concentration of hormones retracted to nutrient utilization and metabolism following intravenous glucose injection between Japanese Black beef heifers, Holstein heifers and dairy cows. Additionally, we examined how these responses changed in each breed as lactation progressed. Plasma concentrations of insulin, glucagon and growth hormone were significantly affected by the glucose injection. However, there was no significant effect on concentrations of insulin-like growth factor I (IGF-I). The responses were similar to those observed in Japanese Black and Holstein heifers. The area under the curve (AUC) of insulin and glucagon were greater for the Japanese Black heifers, while the AUC of growth hormone (GH) and insulin was lower for the Holstein cows. The AUC of insulin and glucagon increased with lactation, while those of GH and IGF-I decreased. The result demonstrated that the utilization of glucose and the hormone responses to glucose injection were different between breeds and stage of lactation.