Linking Canine Teeth Eruption, Testicular Histology and Testosterone Levels as Indicators of Pubertal Maturation in Male Dogs

Puberty in male dogs marks the transition to sexual maturity, characterised by rising testosterone and testicular maturation. While often estimated at 6 months, the absence of birth records frequently complicates age determination. This study evaluated whether permanent canine tooth eruption serves as a reliable, complementary marker for pubertal status alongside chronological age by correlating it with serum testosterone and testicular histology. A sample of 23 male dogs presented for routine gonadectomy were categorised as prepubertal (< 6 months, n = 12) or postpubertal (≥ 6 months, n = 11). Assessments included serum testosterone levels, detailed testicular histology, and the degree of permanent canine eruption. Results revealed that both chronological age at 6 months cutoff and dental eruption (specifically, 2/3 of the permanent canine crown) significantly differentiated prepubertal from postpubertal dogs across key histological parameters. Postpubertal dogs exhibited significantly higher counts of spermatogonia, spermatocytes, and spermatids, alongside larger seminiferous tubule and epithelium areas, and a higher spermatogenic maturation index. However, neither age nor dental criteria were associated with differences in lumen area, Sertoli cell count, or Leydig cell population. While testosterone levels showed a non-significant trend toward being higher in the > 6-month group, they demonstrated a significant positive correlation with the degree of canine eruption. These findings establish that both the conventional six-month age threshold and, more potently, permanent canine eruption are valuable indicators of pubertal status, with dental development providing a superior prediction of underlying endocrine and histological maturation in male dogs.