Dose-dependent effects of tamsulosin on the ejaculation and semen quality in bucks

The objective of this study was to investigate the effect of tamsulosin (TAM) dosages on ejaculation and semen quality. Two sets of Latin square experiment design were applied to 6 bucks receiving normal saline (CON), TAM 134.8 nM/kg (LTAM), or 269.7 (HTAM) nM/kg at 1-week intervals. Semen collection, libido, and ejaculatory scoring were undertaken at 3, 6, 9, 12, and 24 h after injection. Heart rate and body temperature were measured before administration and at 30 min, and before semen collection. The results showed that libido score and heart rate were not affected by treatments. Ejaculatory suppression was observed in both TAM groups. The percentage of ejaculatory suppression was 91.7% by 3 h for both TAM dosages and gradually diminished. Ejaculatory recovery in all bucks was observed by 12 h. Ejaculatory suppression remained unchanged between LTAM and HTAM, but HTAM caused more anejaculation by 6 h (P < 0.05). Some semen parameters of both TAM groups were significantly different from the CON group from 6 to 12 h; however, the values returned to being similar by 24 h. Both TAM dosages had temporary effects on ejaculatory suppression and semen quality, and the effective period was dose-dependent.