The influence of flunixin on the elimination and milk residual patterns of oxytetracycline in dairy goats

This research assessed the impact of flunixin meglumine (FM) co-administration on the elimination and milk residual properties of oxytetracycline (OTC) in dairy goats. OTC was administered via single intravenous (i/v) and intramuscular (i/m) injections at a dose of 10 mg/kg body mass (b.m.). Serum, urine, milk and ruminal juice were analysed using high-performance liquid chromatography (HPLC). The OTC serum concentrations were higher than the MIC for 12 hours against most susceptible pathogens in both groups. The half-lives of the distribution ([T.sub.1/2[alpha]]) and elimination ([T.sub.1/2[beta]] of OTC were 0.24 and 5.79 hours, respectively. The total body clearance was significantly increased in the FM coadministered groups. Following i/m injection, the absorption half-life ([T.sub.1/2ab]) with the maximum absorption time ([T.sub.max]) revealed a rapid absorption rate. Furthermore, the systemic bioavailability (F%) after i/m was 107.2%, indicating complete absorption from the muscular tissues. The bounded fraction of OTC with serum proteins was 18.73%. FM significantly decreases OTC concentration in milk and ruminal juice. OTC is eliminated primarily through the kidneys and to a lesser extent via milk and ruminal juice in dairy goats. Milk obtained from OTC treated goats may not be safe for human consumption two days post administration. Concomitantly, the use of FM with OTC may necessitate the surveillance and optimization of OTC dosage. Key words: oxytetracycline; flunixin meglumine; elimination; milk; residues; goats