Tribulus terrestris extract was added to the water of 10 cocks from the population White Plymouth Rock-mini cocks once daily in dose 10mg/kg body weight for a period of 11weeks. The trial lasted 20 weeks-1week preparatory and 19 weeks experimental period. Eight weeks of the experimental period were intended to measure the aftereffect of the tested product. It was found, that Tribulus terrestris extract improves cocks semen quality : volume of ejaculate, spermatozoids concentration and motility, and shortened the time of methylen blue decolouration. Serum total cholesterol content in the experimental cocks was 9,24% lower (p>0,05) in comparison with the control group. The aftereffect of Tribulus terrestris on the studied parameters was maintained for 8 weeks.

The effect of Bulgarian product Vemoherb-T (dry extract of Tribulus terrestris) on some characteristics of the reproductive capacity of Guinea fowl (Numida meleagris) was studied. A trial was conducted with 30 Pearl-gray Guinea fowls, at the age of 32 weeks, divided in two groups, 12 female and 3 male each. The birds from the two groups were fed the same mixture. The experimental group received the tested product once daily in a dose 10 mg/kg body weight for 12 weeks. The laying intensity, egg morphology and fertility, the weight of testes and ovaries were controlled. It was found a higher laying intensity (P<0.05), similarly higher egg weight (P<0.001), yolk weight (P<0.01), left testes weight (P<0.05) and egg fertility in the experimental group. No significant differences about egg white weight and yolk color between the both groups were found.

The aim of the present research was to investigate the effect of Bulgarian additive Vemoherb-T (dry extract of the annual plant Tribulus terrestris -L), produced by Vemo 99 Ltd Company, Sofia on main biochemical characteristics and hematological parameters of the blood in guinea fowl (Numida meleagris). An experiment was carried out with 30 Pearl-gray Guinea fowl (32 weeks old), distributed in two groups -a control and an experimental, 12 female and 3 male each. All birds were fed the same mixture for breeder guinea fowl. Vemoherb-T was supplemented to the compound feed of the experimental group in a daily dose of 10 mg/kg body weight for a period of 12 weeks.The tested product decreased significantly the levels of total triglycerides (P < 0.05), total cholesterol (P <0.01) and glucose (P < 0.01; P < 0.001 in male and female birds respectively) in the blood serum. It was established significantly higher total protein-((P < 0.001) and calcium (P<0.01) values in the blood serum of the treated birds.The addition of Vemoherb-T increased significantly hemoglobin level, the number of erythrocytes and leukocytes and decreased the number of eosinophils in guinea fowl from the both sexes.

The aim of the study was to determine the effect of different doses of the Bulgarian product VemoHerb-T (dry extract of Tribulus terrestris L.) on the development of reproductive organs in growing male rabbits. In the experiment 35 male rabbits (White New Zealand breed) between 40 and 82 days of age were randomly divided into five groupsa control and four experimental groups. Different doses of VemoHerb-T (2.5, 5, 7.5 and 10 mg/kg body weight for II, III, IV and V group, respectively) were added to the drinking water for the experimental groups. It was found that Tr. terrestris affects the body and testicular weight of male growing rabbits in dose-dependent manner. The dose 2.5 mg/kg of the tested product can be recommended for use in rabbit breeding as the most appropriate and harmless. The higher doses of the extract induced negative histological changes in the rabbits' reproductive organs.

This experiment was designed to evaluate the effect of different doses of Bulgarian product Vemoherb-T (dry extract of Tribulus terrestris) on egg production, serum level of testosterone and histological structure of gonads and kidneys in Japanese quail. In the experiment a total of 52 female and 16 male Japanese quail from Pharaon breed at the initial age of 44 days were involved. Quails were randomly divided in control and three experimental groups, 13 female and 4 male in each. Experimental groups received with the drink water the tested product in following daily doses: 4 mg/kg body weight (10 weeks); 10 mg/kg body weight (the first 5 weeks of the trial); 10 mg/kg body weight (10 weeks) for I st , II nd , III rd treated groups respectively. A significant increase of ovary weight in quails from III rd experimental group (P < 0.01) in comparison with the control was measured. Egg production in II nd and III rd treated groups increased significantly (P < 0.01) than the control group. Testosterone level of males from III rd experimental group enhanced significantly (P < 0.05; P < 0.01) than other groups. The ovary core part of females from III rd experimental group contained a much lower number of mature follicles in comparison to the other groups and its central medulla was highly vascularized. Tribulus terrestris extract in a dose of 10 mg/kg stimulates the production of male reproductive cells, while the dose of 4 mg/kg caused a delay of spermatozoa production. Histological analysis showed that in all experimental groups the structure of the kidneys was preserved and that the higher doses lead to certain reduction of the parenchyma.