A randomized controlled trial of dexamethasone as an adjunctive therapy to propylene glycol for treatment of hyperketonemia in postpartum dairy cattle

Abstract Treatment of hyperketonemia with oral propylene glycolhas proven efficacy but the cure rate remains moderate. Dexamethasonehas long been suggested as a treatment for hyperketonemia, even though evidence of its efficacy is contradictory. The objective of this randomized controlled trial was to evaluate the effect of adding a single intramuscular injection of 20mg of dexamethasoneto oral propylene glycoltherapy for hyperketonemia [blood β-hydroxybutyrate (BHB) ≥1.2mmol/L]. All cows between 3 and 16d in milk on 4 dairy farms in New York State were tested once weekly for hyperketonemia using a handheld ketone meter. All enrolled animals received 312g (300mL) of propylene glycolorally once daily for 4d and either a single injection of dexamethasoneor an equivalent volume of sterile saline. A total of 509 animals were enrolled, with 254 and 255 in the placebo and dexamethasonegroups, respectively. Treatment with dexamethasonedecreased the oddsof being hyperketonemic in the second week posttreatment; however, the oddsof hyperketonemia in the first week posttreatment only decreased in those animals that were treated at a BHB blood concentration between 1.2 and 1.5mmol/L. For the 8% of cows with blood BHB >3.2mmol/L at enrollment, receiving dexamethasoneincreased the oddsof being hyperketonemic the following week. We detected no difference between treatment groups in the oddsof postpartum disease or in milk production. For cows with initial BHB of 1.2 to 1.5mmol/L, treatment with dexamethasonetended to reduce the oddsof pregnancy at first insemination. Based on the small and conditional benefits of dexamethasoneand a lack of difference in milk yield or disease incidence, we do not recommend the use of dexamethasoneto treat hyperketonemia.