Magnitude and Duration of Effects of Two Corticosteroid Formulations (Dexamethasone Sodium Phosphate and Phenyl Propionate; Prednisolone Acetate) on Blood Glucose, Leukocyte Values, and Milk Yield in Dairy Cows

Abstract

The magnitude and duration of the effects of two corticosteroid formulations were determined on blood glucose and leukocyte values and milk yield in normal, lactating dairy cows. One formulation contained a combination of dexamethasone sodium phosphate and dexamethasone phenyl propionate (DEX). The other contained prednisolone acetate (PRED). Blood samples were obtained prior to and at 6, 24, 48, 72, 96, and 144 hours following administration of a single dose of DEX or PRED. Milk yield was determined for two days prior to drug administration and for seven days afterwards. Both corticosteroids caused significant increases in blood glucose values, although DEX caused significantly larger and longer lasting increases. DEX also caused significant leukocytosis and neutrophilia. PRED caused significant, very short lasting neutrophilia, but had no significant effect on total blood leukocyte values. Both drugs caused significant reductions in blood eosinophil and lymphocyte values, and significant increases in monocyte values. DEX also caused a significant, marked drop in milk production on days 1, 2, and 6, post-administration. PRED did not significantly affect milk production. Because DEX produced more dramatic and persistent changes in blood glucose values and milk production than did PRED, the authors believe that DEX is likely to be more efficacious than PRED for treating ketosis in dairy cows. Because DEX produced more dramatic and persistent effects on blood neutrophil values than PRED, it is also likely to be a better option for use as an anti-inflammatory drug.