Evaluation of the parameters of variability of the productivity of kholmogory breed bulls

For the first time in Russia a mathematical analysis of sperm production of Kholmogory stud bulls will be performed based on a linear equation model. The aim of the research was to evaluate the parameters of variability of the productivity of Kholmogory stud bulls based on a linear equation model. The object of the study was Kholmogory stud bulls (n = 72) born and used mainly in the Komi Republic. The main aspects of sperm productivity that were the subject of the study include the following parameters: "proportion of live sperm", "sperm concentration", "proportion of sperm with PPD, (%)", "number of sperm with PPD in a dose", "number of sperm with intact acrosome", "number of sperm with abnormal morphology", "sperm survival at 38°C, h". The collected data were analyzed using a mixed equation model approach with the REMLF90 restricted maximum likelihood program. The highest values of the genetic correlation coefficient were found for such sperm production parameters as "sperm concentration, million/ml" - it was reliably positively associated with "the number of sperm with PPD in a dose, million" and "the number of sperm with an intact acrosome, %". In this case, the correlations were at the level of r=0.6-0.8. "The number of sperm with abnormal morphology, %" positively correlated with "the proportion of live sperm, %" and with the "sperm survival at 38°C" parameter. Negatively strong reliable relationships were not established either for the values of genetic or paratypic correlations. Low heritability of sperm productivity parameters (0.039…0.112) indicates that the influence of genetics on these parameters is small. Among these parameters, the highest heritability coefficient was demonstrated by the parameter “sperm survival at 38°C” (0.322). In light of the analysis of sperm productivity as a complex of parameters, it can be stated that this system demonstrates significant stability and variability, which emphasizes the importance of taking into account various aspects when assessing sperm productivity.