Short communication: Pharmacological semen collection in dogs via urethral catheterization: evaluation of cardiorespiratory stability and semen quality under continuous dexmedetomidine infusion.

Pharmacological semen collection (PSC) via urethral catheterization employs α2-adrenergic agonists to induce semen emission. While dexmedetomidine is effective for PSC at doses of 15-20 µg/kg, doses above 3 µg/kg in dogs are associated with notable cardiorespiratory adverse effects. This study evaluated the safety and efficacy of a low-dose sedative protocol for PSC in domestic dogs. Ten male dogs were sedated with intramuscular dexmedetomidine (3 µg/kg) combined with ketamine (3 mg/kg). After 10 min, a continuous dexmedetomidine infusion (3 µg/kg/h) was initiated, and following 10 min of infusion, a propofol bolus (1-2 mg/kg) was administered to allow catheterization and semen collection. Heart rate, respiratory rate, and mean arterial pressure were continuously monitored. Semen samples were analyzed for macroscopic characteristics (color, volume, pH) and microscopic parameters (sperm morphology, plasma membrane integrity). Sperm concentration, and kinectics were assessed using a portable computer-assisted sperm analysis system. The protocol maintained stable cardiopulmonary parameters in all animals. Two dogs did not emit semen; however, the remaining eight yielded samples with a mean volume of 15.49 ± 2.98 µL and a sperm concentration of 693.69 ± 116.15 million spermatozoa/mL. Motility parameters included total motility (20.74 ± 5.17%), progressive motility (12.80 ± 4.32%), curvilinear velocity (51.79 ± 4.04 μm/s), and sperm linearity (22.00 ± 1.68%). The mean proportion of sperm with intact plasma membranes was 53.16 ± 2.52%. In conclusion, the proposed protocol was safe and moderately effective for PSC in dogs; however, the suboptimal semen quality underscores the need for further refinement.