Effect of in ovo thermal manipulation on rooster semen quality during hot climatic condition

Thermal manipulation during embryogenesis improves adaptation to heat stress in adult chicken. The aim of the present study was to evaluate the effect of higher temperature during incubation on rooster semen quality during hot climatic condition. Male chicks hatched from normal incubation temperature (37.5°C and 65% relative humidity; Control-C) and higher incubation temperature (39.5°C and 65% relative humidity; heat exposed-HE) provided between 16–18^th day of incubation for 3 hours each day were reared and evaluated for semen quality during high ambient temperature (Temperature Humidity Index (THI)-80.94). At 64 weeks of age semen from eight roosters from each group was collected and evaluated for different gross semen parameters, hypo-osmotic swelling test, sperm chromatin damage and seminal plasma cortisol. The results showed no significant difference between the groups in any of the parameters studied except for abnormal sperm that were lower in the HE birds. It was concluded that higher temperature during incubation reduced abnormal sperm percent during heat stress. However further research on duration and time of heat treatment during incubation is needed to bring overall improvement in rooster semen quality during heat stress.