A study of the influence of the method of oral administration of ampicillin upon plasma drug levels in calves.

Ampicillin was given orally to five Holstein calves using the following four different methods of administration: via stomach tube, mixed and fed in the calf starter ration, dissolved in milk and pail fed and administered orally as 400 mg commercial calf tablets. In addition, ampicillin was dissolved in milk and pail fed 20 to 30 minutes following intramuscular atropine. Ampicillin was only detected in the plasma of calves which had received the drug, pail fed in milk. Atropine administration slowed the appearance of the drug in the plasma but did not decrease the efficiency of absorption.