Determination of milk concentrations and pharmacokinetics of salicylic acid following acetylsalicylic acid (aspirin) administration in postpartum dairy cows

Abstract

The objectives of this descriptive study were to 1) describe the pharmacokinetics of salicylic acid (SA) in the milk and plasma of postpartum dairy cattle following oral administration of ace­tylsalicylic acid (ASA) (aspirin); 2) to estimate a recommended milk withdrawal period for dairy cattle treated with ASA; and 3) to determine the impact of ASA administration on plasma prostaglandin E2 metabolite (PGEM) concentrations. Adminis­tration of non-steroidal anti-inflammatory drugs, such as the widely available drug aspirin, or acetylsalicylic acid (ASA), may improve health and milk production in postpartum dairy cows. However, plasma pharmacokinetic data for salicylic acid (SA), the active metabolite of ASA, are unrepresentative of lactating dairy cows and current treatment regimens, and there are cur­rently no published milk residue and minimal pharmacody­namic data available for ASA or SA in dairy cows.