Acetylator phenotype in black-and-white breed and BW x HF cross-breed calves

The aim of this study was to determine the effect of breed on acetylator phenotype in calves of different ages. The experiment was carried out on 80 healthy calves: 40 of BW (Black-and-White) breed and 40 Black-and-White x Holstein-Friesian (HF) cross-breed (50% HF). The acetylator phenotype in 10-day old and 60-day old calves was determined by using sulphadimidine as a model drug, according to the method described by Evans (8). In the population of Black-and-White calves 24 (60%) had slow and 16 (40%) had fast acetylators. 14 (35%) slow and 26 (65%) fast acetylators were observed in cross-breed calves (50% HF). The results between BW and 50% HF calves differed significantly (p = 0,01). It was also observed that the frequency of slow and fast acetylators in the 10-day old and 60-day old animals were very similar and not statistically different. These results indicated that age does not influence acetylation of sulphadimidine in calves. In conclusion, the study demonstrated that genotype modifies acetylator phenotype in calves. The examined population of 50% HF calves had significantly more fast acetylators compared with calves of Black-and-White breed. It was obvious, then, that cattle breed has an influence on the frequency of slow and fast acetylators. This is clinically significant because the risk of undesirable symptoms due to the toxic effect of many drugs and other xenobiotics occurs in slow acetylators.