The factors influencing qualitative and quantative indices of native sperm of bulls of JVC "Krasnoyarskagroplem"

It is known that qualitative and quantitative indi-ces of sperm are not constant and depend on such factors as genotype, health, animals' age, valuable feeding, the technology of keeping and operation and also the season. Now in Russia young bulls are selected by origin to the exterior and develop-ment. As bulls-sires have great influence on herd and breed in general, it is necessary to estimate the bull on the indicators of reproductive ability. In this regard the need of quality check of sperm of bulls increases, it will help to reveal in due time bulls-sires with low reproductive ability. For this purpose the sperm of the bulls of red and motley and Hol-stein breed of red and motley population of JSC ‘"Krasnoyarskagroplem", located in the village of Solontsy, Krasnoyarsk Region was investigated on the following parameters: sperm volume, ml; sperm concentration in one ml, bln/ml; the concentration of spermatozoa in sperm, bln; the sperm obtained in average per bull, ml; native semen defect, ml; the percentage of defect, per cent. Conducted re-searches showed that the season of the year had impact on bulls spermoproduсtion. Bulls-sires of Holstein breed of red and motley population were most sensitive to changes of the seasons of the year; however, the bulls of red and motley breed differed more in the best indicators of sperm. At the research of indicators of sperm depending on age it was found out that the bulls at the age of 2.1-3 years had the minimum indicators of native sper-moproduction which testified about the period of formation of sexual functions. To 4.1-5 years of age the indicators of spermoproduction reach high values, but decrease after 5 years.