Acute Metabolic Responses of Postpartal Dairy Cows to Subcutaneous Glucagon Injections, Oral Glycerol, or Both

• Published in: Journal of dairy science Vol. 91; no. 9; pp. 3311 - 3322
• Main Authors: Osman, M.A, Allen, P.S, Mehyar, N.A, Bobe, G, Coetzee, J.F, Koehler, K.J, Beitz, D.C
• Format: Journal Article
• Language: English
• Published: Savoy, IL American Dairy Science Association 01.09.2008; Am Dairy Sci Assoc
• Subjects: 3-Hydroxybutyric Acid - blood; acute metabolic responses; Administration, Oral; Animal productions; Animals; Biological and medical sciences; Blood Glucose - metabolism; Blood Urea Nitrogen; Cattle - metabolism; combination drug therapy; dairy cows; Dairying; energy balance; Fatty Acids, Nonesterified - blood; fatty liver; Female; Food industries; free fatty acids; Fundamental and applied biological sciences. Psychology; glucagon; Glucagon - administration & dosage; Glucagon - blood; Glucagon - pharmacology; glycerol; Glycerol - administration & dosage; Glycerol - pharmacology; Holstein; hormonal regulation; hormone secretion; Injections, Subcutaneous; Insulin - blood; lipid metabolism; metabolic studies; Metabolism - drug effects; metabolites; Milk and cheese industries. Ice creams; oral administration; postpartum interval; Postpartum Period - metabolism; Random Allocation; subcutaneous injection; Terrestrial animal productions; Triglycerides - blood; Vertebrates; Vertebrata; Farming animal; Mammalia; Glucagon; Subcutaneous; Dairy cattle; Dairy industry; Glycerol; Artiodactyla; Injection; Metabolism; Ungulata
• ISSN: 0022-0302; 1525-3198
• DOI: 10.3168/jds.2008-0997

This study examined the effects of multiple subcutaneous glucagon injections with or without co-administration of oral glycerol on energy status-related blood metabolites and hormones of Holstein dairy cows in the first 2 wk postpartum. Twenty multiparous cows were fed a dry cow ration supplemented with 6 kg of cracked corn during the dry period to increase the likelihood of developing postpartal fatty liver syndrome. Cows with a body condition score of >=3.5 points (1- to 5-point scale) were assigned randomly to 1 of 4 treatment groups: saline, glucagon, glycerol, or glucagon plus glycerol. Following treatment, serial blood samples were collected over an 8-h period to determine the effects of glucagon and glycerol on blood metabolites and hormones. Treatment effects were determined by comparing the concentrations of metabolites and hormones during the first 4-h period and the entire 8-h period after treatment administration (time 0) with the concentration of the same compounds at time 0 on d 1, 7, and 13 postpartum. Administration of glucagon alone increased concentrations of plasma glucagon and insulin on d 1, 7, and 13 and increased plasma glucose and decreased plasma nonesterified fatty acids (NEFA) on d 7 and 13 postpartum relative to the saline group. Administration of glycerol alone increased plasma glucose on d 7 and plasma triacylglycerols on d 1 postpartum. Glycerol administration also decreased plasma glucagon and NEFA on d 1, 7, and 13 and plasma β-hydroxybutyrate (BHBA) on d 1 postpartum relative to the saline group. Administration of glucagon plus glycerol increased and sustained concentrations of plasma glucagon, glucose, and insulin on d 1, 7, and 13 and decreased plasma NEFA on d 1, 7, and 13 and BHBA on d 1 and 7. Early postpartal treatment of dairy cows with glucagon plus glycerol increased plasma glucose and insulin, decreased plasma NEFA and BHBA, and increased secretion of liver NEFA as plasma triacylglycerols. This suggests that glucagon and glycerol, when co-administered, act to decrease the likelihood of metabolism-related syndrome development in dairy cows.