EN
Four groups of male golden hamsters (12 animals per one group) were given orally for 5 consecutive days the following drugs: group I = 0 (control), group II = monensin at the rate of 2 mg per 1 kg, group III = tiamulin at the rate of 45 mg per 1 kg, group IV = monensin simultaneously with tiamulin at the rate of 0.5 mg and 10 mg per 1 kg respectively. Four animals of each group were sacrificed at 1, 4 and 10 weeks after the treatment. There were evaluated: the weight of testes, epididymides, accessory sex glands, the number of spermatozoons and the percentage of spermatozoons with morphological defects. The results were analysed statistically with Bartlett’s test and two-way ANOVA. Neither monensin nor tiamulin induced any adverse effects on the male reproductive system of hamsters.