Content of endogenous hormones in the blood serum of milking breeds bulls-producers in the conditions of Tatarstan region

Abstract

Relevance and methods . 35 bulls-producers of milking breeds (holstein of black-and-white paint, holmogorskaya of Tatar type with flow of holstein blood, black-and-white) were inspected in the age 1,8–8 years old in the autumn season in conditions of Tatarstan Republic (Volga region, Povolzhye). The subject of the work is to research the concentration of endogenous hormones (testosterone, estradiol, thyroxin) and their precursor — cholesterol in the blood serum in the day of semen collection and their intercommunication reproductive function. Results. Was established that, depending of the breed there are differences in concentration of endogenous hormones in the blood serum. Total number of spermatozoids in ejaculate has positive relation with testosterone content in the blood serum in the day of collection semen: the higher level of testosterone, the higher concentration of spermatozoids in ejaculate (P < 0.001). The lowest level of endogenous hormones and cholesterin is registered in holstein breed of Holland selection. The age wields major influence on content of endogenous hormones: on concentration of testosterone in the blood serum, of estradiol and thyroxin (P < 0.05). Unascertained is interaction of the age and the containing of cholesterin. Suggested during andrological health examination of bulls-producers to monitor the content of endogenous hormones in the blood serum as extra test for diagnostic of reproduction function of animals.