Relationship Between Testicular Morphometry, Vascular Waveform Pattern, Semen Picture, and Specific Serum Testosterone Levels in Baladi bucks Approaching Puberty

This study aimed to determine testicular blood flow with semen imaging and describe accompanying variations in mediastinal thickness (MT), serum testosterone, and semen characteristics in Baladi bucks approaching puberty and sexual maturity. From 5–10 months of age, Baladi bucks (n = 5) underwent B-mode imaging, Doppler scanning, and blood sampling for testosterone assaying once a month. From 7 months, semen was collected and evaluated. The first semen was collected at a mean age of 7.2 months, while the first spermatozoa appeared at 8.3 months, and the mean age of sexual maturity was 9.4 months. The highest semen volume (1.02 ± 0.09 mL), motility (mass score = 5 and individual = 78.00 ± 1.58%), morphology (94.74 ± 1.99%), alive% (85.21 ± 1.32), and semen concentrations (5.24 ± 0.32 109/mL) were noted in buck 4 (9.5 months; 25.0 kg) followed by others. Testicular width (TW) and MT were positively correlated (r = 0.71; P = 0.03) and increased from 8–10 months (P < 0.05). The spectral graph of young bucks revealed an absent end velocity point. Testicular flow expressed by colored area/pixels was positively correlated with age (r = 0.855), accompanied by increased testosterone levels. Semen characteristics and Doppler parameters were not significantly correlated, except Doppler indices negatively correlated with progressive motility percentage. In conclusion, only the testicular Doppler indices are useful for evaluating testicular function and selecting bucks for breeding since these were the only variables negatively correlated with progressive motility percentage. The spectral Doppler velocities are not useful in estimating the full picture of semen quality in sexually mature bucks. These values should be assessed cautiously since many alterations could lead to the elevation or decline of testicular Doppler parameters.