Impact of Ejaculate Collection Interval and Preservation Extenders on Semen Traits of the Indigenous Dong Tao Chicken Breed

Background: The Dong Tao chicken is a rare indigenous Vietnamese breed of high cultural and genetic value, yet limited reproductive performance constrains its conservation and wider use in poultry production. Optimizing semen collection protocols and storage methods is essential for supporting artificial insemination programs. Aims: This study evaluated the effects of semen collection frequency and short-term cold storage using different extenders on semen quality in Dong Tao roosters. Results: In Experiment 1, semen collection every three days yielded superior ejaculate characteristics compared with daily or weekly intervals. Roosters collected every three days produced significantly greater semen volume (0.42 0.01 mL vs. 0.21 0.03 mL daily), higher sperm concentration (3.26 0.14 vs. 2.52 0.37×10⁹/mL), and the lowest abnormal morphology (8.26 1.12% vs. 16.37 2.99% daily; p < 0.05). In Experiment 2, semen stored for 24h at 5C with the Leik extender preserved superior quality compared to Tyrode and physiological saline. Leik maintained the highest straight-line velocity (20.05 2.03 m/s), greater amplitude of lateral head displacement (17.41 6.08 m), and the lowest abnormality rate (14.98 3.91%) relative to Tyrode (20.84 4.62%) and saline (26.78 5.38%). Conclusion: Collecting semen at three-day intervals combined with the use of Leik extender for short-term cold storage provides an effective and practical protocol for enhancing semen quality in Dong Tao roosters. This strategy offers important applications for artificial insemination and contributes to the genetic conservation of indigenous poultry breeds.