EFFECT OF ORAL-ADMINISTRATION OF FLUNIXIN MEGLUMINE ON THE INFLAMMATORY RESPONSE TO ENDOTOXIN IN HEIFERS

Objective-To compare the effect of oral and IV administrations of flun ixin meglumine on the endotoxin-induced inflammatory response in heife rs. Design-The study was conducted in 2 experimental sets in which hei fers were exposed to low IV doses of Escherichia coil endotoxin. Withi n each set, heifers were allocated to 3 treatment groups; pretreatment with flunixin meglumine orally and IV prior to endotoxin administrati on, or endotoxin administration only. The dose of flunixin used was th e recommended therapeutic dose in cattle. Animals-11 clinically normal heifers weighing from 400 to 640 kg. Procedure-A permanent cannula wa s inserted into the jugular vein on the day prior to the experiment. B lood samples were collected regularly during the experiment and analyz ed for the content of prostaglandin F-2 alpha metabolite, cortisol, bl ood mononuclear cells, and polymorphonuclear neutrophilic leukocytes a nd rectal temperature was measured. Results-Endotoxin administration c aused clinical signs and hematologic changes characteristic of endotox emia in cattle. Flunixin administered orally prior to experimentally i nduced endotoxemia exerted an effect equal to that after its IV admini stration. Significant increases in rectal temperature and prostaglandi n F-2 alpha metabolite concentrations after administration of endotoxi n were abrogated when the heifers were pretreated with flunixin, irres pective of route of administration. Cortisol concentrations were lower after pretreatment with flunixin. However, flunixin did not prevent t he decrease in blood mononuclear cells and polymorphonuclear neutrophi lic leukocytes seen after endotoxin administration. Conclusion-Owing t o no major difference in the inflammatory response between oral and IV flunixin dosing, flunixin granules may be an alternative to parentera l use in bovine practice.