[Concentration and retention time of ampicillin trihydrate in the blood serum when used internally with ruminants].

Studied was the resorption of ampicillin-trihydrate in the digestive tract and its retention in the blood serum of lambs (at rates of 20, 30, and 50 mg/kg body weight), sheep (at rates of 50, and 70 mg/kg body weight), and calves (at rates of 30, 50, and 70 mg/kg b. w.) when applied in the form of a 10 per cent water sus ensior and gelatine capsules. It was found that the blood levels and the time of retention of ampicillin at its oral application to ruminants were directly correlated with the amount applied, the drug form of the antibiotic, and the age of the animals. The oral use with calves aged 15 days at the rates mentioned in the form of a water suspension diluted with milk led to peak concentrations at the second hour. In this case ampicillin-trihydrate was retained in the blood serum in the course of 12 hr regardless of the amount applied. The serum levels of the product in 2.5-month-old calves used at 50 and 70 mg/kg in the form of a water suspension were either traces or could not be defined at all, while in calves at the same age the milk-diluted ampicillin suspension in the doses referred to showed bacteriostatic concentrations.