Acute and chronic metabolic responses of transition dairy cows with fatty liver disease to subcutaneous glucagon injections, oral glycerol, or both

Abstract

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 two wks 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 disease. Cows with a body condition score of ≥ 3.5 points (1-5 point scale) were assigned randomly to one of four treatment groups: saline, glucagon, glucagon plus glycerol, and glycerol. Following treatment, serial blood samples were collected over an 8-hr period to determine the effects of glucagon and/or glycerol on blood metabolites and hormones. Treatment effects were determined by comparing the concentration of metabolites and hormones during the 8-hr period after treatment administration (time 0) with the concentration of the same compounds at time zero on d 1, d 7, and d 13 postpartum. Glucagon alone tended to increase concentrations of plasma glucose on d 7 and d 13 postpartum (P = 0.07 and P = 0.06, respectively) and glucagon on d 13 (P= 0.08), and increased insulin on d 1 and d 7 (P = 0.04 and P = 0.01, respectively) and decreased concentrations of plasma nonesterified fatty acids (NEFA) on d 13 postpartum (P = 0.04) relative to the saline. Administration of glucagon plus glycerol increased and sustained postpartal plasma glucose on d1, d 7, and d 13 (P =