Interrelationship between ram plasma testosterone level and some semen characteristics

Abstract

A total number of 6 rams (breed Rahmani) were used in this experiment to determine the effect of testosterone level before and after semen collection on semen evaluation. After semen collection, semen samples were subjected to evaluation of the following criteria: initial sperm motility percentage, methylene blue reduction time test (MBR-T), sperm concentration per mililitre, semen volume and reaction time (RT). These criteria were measured for first and second semen ejaculates, respectively. All the rams were allowed to exert a false mounting before blood sample collection and second blood sample was collected after second semen ejaculate collection. Data showed that there were no significant differences between testosterone levels before first semen collection and after second semen collection. These levels were 5.46 ± 1.01 and 6 ± 1.06 ng/ml of blood serum. But there were significant differences among different rams. These levels were 4.21 ± 0.93, 9.27 ± 1.95, 5.57 ± 2.17, 5.96 ± 1.93, 2.51 ± 0.83 and 5.42 ± 1.98 ng/ml of blood serum for 6.0 different rams, respectively. In addition, there was a high correlation between testosterone levels and semen characteristics. Testosterone levels correlated significantly with sperm motility, sperm concentration and methlyene blue reduction time test. These correlations were 0.83, 0.84, 0.87 and -0.82 for the above mentioned criteria, respectively. It could be concluded that testosterone levels could be a detrimental factor in semen assessment.