[Ampicillin tolerance and content in the mammary gland of lactating cows and sheep]

Experiments were carried out with lactating cows and ewes consisting in the intramammary application of ampicillin-trihydrate with the use of syringe cannules, and with paraffin and vaselin as constituents. Cows were treated with 10 cm3 (500,000 IU) (in the respective quarter of the udder), and ewes--with one half of the syringe content. The milk of the treated animals was sampled prior to manipulation, at the 24th, the 48th, 72nd and 96th hour in order to follow up the time during which the antibiotic was retained in the milk as well as the changes in the cell content and the hydrogen ion concentration. It was found that ampicillin persisted in milk up to the 48th hour in therapeutic concentrations. At the 96th hour the milk proved free of the antibiotic in both cows and ewes and could be offered for consumption or technologic processing.