It is difficult to objectively assess the functional state of the endocrine gland based on the level of hormones in the blood, since hormones vary significantly in absolute values during the day. Therefore, to assess the functional state of the endocrine glands in biological and medical practice, "load" is used. The criterion for evaluating the state of the gland is the change in the concentration of secreted hormone by the endocrine gland in response to the stimulation. As is known, the testis reacts relatively quickly to stimulation with chorionic gonadotropin. This allows us to determine the limiting features of the hormone-synthesizing and hormone activity of the testes and determine the maximum response of the testes to this stimulation. The object of the study was 6-month-old boars of large white breed, Landrace and tempo, 10 heads from each breed. In order to determine the functional endocrine reserves of the testes at 6 months of age, CG (chorionic gonadotropin) was administered intramuscularly at a dose of 1000 IU. HCG was administered 3 times every 72 hours. Blood for the determination of testosterone was taken before administration of HCG and 2.12,24,48 and 72 hours after its administration. Testosteron was determined by the enzyme immunoassay. Sperm counts in 18-month-old boars were studied using standard methods. Performed three-fold loads with an interval of 72 hours showed that the hormone level increased to 7.2±0.6 nmol/l in a large white breed 72 hours after the first administration of HCG, in the Landrace breed to 7.9±0.5 nmol/l, in the Duroc breed to 7.0±0.7 nmol/l, in the tempo breed to 7.0±0.6 nmol/l. After the second injection HCG the testosterone levels in large white breed boars increased by 1.2 nmol/l, and breeds Duroc 1.7 nmol/l, Landrace 0.1 nmol/L. In the boar breed, tempo increased the hormone by 0.4 nmol/l. In this regard, the increase in testosterone in experimental boars continued, which means that the reserves of endocrine function of the testes were not fully realized, so the 3rd stimulation of HCG was also performed. In a large white breed of boars and Duroc, the maximum concentration of testosterone was observed 24 hours after administration of HCG and was 9.2±0.7 and 8.9±0.5 nmol/l respectively. In the Landrace and tempo breeds, the maximum concentration of testosterone was 2 hours after 3 CG stimulation and was 8.2±0.6 and 7.5±0.6 nmol/l. respectively. In terms of sperm, its fertilizing capacity and the production of live piglets per Farrow, the indicators were higher for boars of large white breed and Duroc.