The use of clinoptilolite is an effective means of increasing the gain and live weight of calves. The application does not cause difficulties in the methods of introducing the additive to calves. Natural clinoptilolites of various deposits are presented in a wide range on the feed additives market. Aims: The objective of the work was to study the effectiveness of natural mineral clinoptilolite on physiological and zootechnical indicators of growth and development of calves. Methodology: The

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... y was carried out on 39 clinically healthy Holsteinized black-and-white calves selected at random, 13 animals per group. For 85 days, the calves of the experimental group received a basic diet enriched with natural mineral clinoptilolite to increase the efficiency of growth and development at a dosage of 25-50 and 50-100 g / head / day. Blood samples were taken from the jugular vein at the end of the supplement feeding (n = 5) for physiological, biochemical and immunological studies. Results: In the course of the study, it was found that in the experimental groups there were higher gains in live weight by 7.3 and 4.7% in comparison the control, and low feed costs per 1 kg of gain. Feeding clinoptilolite promoted an increase in the concentration of Ca in the blood of calves of the dairy period by 14.2% (p <0.05), an increase in phagocytic activity by 4.87 (p <0.05), the phagocytic number was higher by 0.20 (p < 0.05) units. Conclusion: The totality of the information presented confirms the physiological adequacy for calves to the introduction of natural mineral clinoptilolite in the indicated dosages.