Glucose Kinetic Responses to Protein Supplementation and Exogenous Somatotropin in Late Gestation Dairy Cows

• Published in: Journal of dairy science 1999-06, Vol.82 (6), p.1274-1281
• Main Authors: Putnam, D.E., Varga, G.A., Green, M.H.
• Format: Article
• Language: English
• Subjects: Animal productions; Animals; Biological and medical sciences; Blood Glucose - metabolism; Body Weight; Cattle - blood; Dietary Proteins - administration & dosage; Female; Fundamental and applied biological sciences. Psychology; Gestational Age; glucose; Growth Hormone - pharmacology; Kinetics; Pregnancy; protein; somatotropin; Terrestrial animal productions; Vertebrates
• ISSN: 0022-0302; 1525-3198
• DOI: 10.3168/jds.S0022-0302(99)75350-6

Glucose kinetics were measured in late gestation multiparous Holstein dairy cows fed diets with different amounts of dietary crude protein (13.3 vs. 17.8%), with and without exogenous somatotropin. The trial was conducted as a completely randomized design; 35 cows were used in the final analysis. Kinetic measurements were made using the single injection technique with uniformly labeled 13C-labeled glucose. A diet that contained 17.8% crude protein appeared to increase glucose utilization without a corresponding increase in supply. The evidence was an increased rate of glucose disposal. In contrast, exogenous bovine somatotropin (Posilac®, Monsanto Co., St. Louis, MO) appeared to enhance glucose conservation, as indicated by a tendency for a decreased fractional catabolic rate and an increased glucose pool size. Somatotropin appeared to modify glucose metabolism in a pattern favorable for supporting terminal fetal development and lactogenesis and for maintaining or enhancing maternal glycemia. The latter pattern could have implications for improving the health of periparturient dairy cows.