EN
The aim of this study was to compare of pharmacokinetics of caffeine in calves of the Black-and-White (BW) breed and cross-breed Black-and-White x Holstein-Friesian (BW x HF (50% HF)) calves. The effect of age on “interbreed” differences in the values of selected pharmacokinetic parameters of this model drug was examined. The experiment was carried out on 20 healthy calves: 10 of BW breed and 10 cross-breed. The caffeine test was performed in calves aged 10, 20 and 40-days-of-life. The animals received caffeine per os at a dose of 5 mg/kg body weight. The concentration of caffeine in the plasma was determined by the EMIT (enzyme-multiplied immunoassay technique) method. The pharmacokinetics of caffeine were calculated through a non-compartmental method, using The TopFit computer software. The obtained results indicate that the age of calves had an influence on the values of pharmacokinetic parameters of caffeine. We observed that estimated pharmacokinetic parameters of caffeine differed significantly between 10, 20 and 40-day-old calves (P < 0.05; P < 0.01). Moreover, it was stated that pharmacokinetic parameters of caffeine in Black-and-White and 50% HF cross-breed calves do not differ significantly.