Rapid and prolonged distribution of tulathromycin into lung homogenate and pulmonary epithelial lining fluid of Holstein calves following a single subcutaneous administration of 2.5 mg/kg body weight.

Abstract

Twenty-four healthy Holstein calves received single subcutaneous injections of 2.5 mg/kg bw tulathromycin. At each of 8 time points ranging from 1 – 360 hr post-dose, three animals were randomly selected for euthanasia. At the time of euthanasia, whole blood, lung tissue, and broncho-alveolar lavage (BAL) samples were collected and subsequently assayed for tulathromycin with an LC MS/MS procedure. Concentrations of tulathromycin in pulmonary epithelial lining fluid (PELF) were determined from