Abstract:
The present study was aimed at studying the influence of seasonal parameters (ambient temperature, atmospheric pressure, air humidity, duration and gradient of daylight hours) on the quantitative and qualitative parameters of sperm (volume, motility, concentration, survival) of rams bred in mid-latitude. Sperm samples were collected from 5 Dzhalginsky merino rams once a week for twelve calendar months using an artificial vagina. The lowest quality sperm was produced in the spring, high quality indicators were observed in the autumn period (semen volume: 0.96 ± 0.14 ml versus 1.42 ± 0.15 ml, P <0.05; sperm concentration (× 109 ml-1 ): 2.66 ± 0.10 versus 3.61 ± 0.11, P <0.001; total sperm (× 109): 2.56 ± 0.06 versus 5.12 ± 0.09, P <0.001; motility (1-10) 7.42 ± 0.55 versus 9.08 ± 0.57, P <0.05; relative survival: 35.85 ± 2.94 h versus 67.4 ± 2.77 h, P <0.001). The results revealed strong positive correlations between semen quality parameters (P <0.001). The most significant negative correlation was found between semen volume and daylight hours (r = - 0.638; P <0.001). With a 95% probability, a curvilinear correlation was established between the length of daylight and the semen volume (yv= 0.31±015). In conclusion, it should be noted that the season of the year influences the quality of the rams sperm, with the value and direction of the daylight gradient having the greatest influence. It is with a negative gradient aimed at reducing the length of daylight that the highest rates of ram sperm are observed.