Effect of Seasons on the Quality of Fresh Semen in Thai Native Chickens: Deang Dok Koon and Pradu Hang Dam

抄録

This study investigated the impact of seasonal variations on the quality of fresh semen in two Thai Native chicken breeds: Deang Dok Koon (DDK) and Pradu Hang Dam (PD). A 3 × 2 factorial experiment was conducted using a completely randomized design (CRD). The factors considered were season (summer, rainy, and winter) and breed (DDK and PD). Twelve roosters per breed (aged 1 year) and 40 commercial laying hens were housed in open-air conditions. Semen was collected twice a week for 24 weeks (48 total collections). Semen volume, mass movement, sperm progressive motility, sperm concentration, total sperm count, sperm viability, sperm morphology, and fertility were evaluated. No significant interaction was found between season and breed. While the season did not affect mass movement, sperm progressive motility, and total sperm count, it significantly influenced semen volume, sperm concentration, sperm viability, sperm morphology, and fertility. Winter had the highest sperm concentration (4.51 × 10⁹ sperm/mL), followed by summer (4.16 × 10⁹ sperm/mL) and the rainy season (3.82 × 10⁹ sperm/mL). Summer had the lowest sperm viability (93.45%), whereas rainy (95.49%) and winter (95.22%) seasons were similar. Sperm morphology was higher in summer (6.79%) than in the rainy season (5.66%) and winter (5.18%); however, the rainy season and winter were not significantly different. Fertility rates were highest in winter (86.81%) and the rainy season (85.88%), with summer (77.99%) being the lowest. Breed significantly affected mass movement, sperm progressive motility, sperm concentration, and sperm viability, but not fertility. The PD breed showed superior semen quality compared to DDK. Overall, seasonal variations significantly impacted fresh semen quality, with winter providing optimal conditions compared to summer and rainy seasons.