Type of Extender and Equilibration Time as Factors Affecting Post-Thaw Quality Characteristics of Turkey Semen

Commercial turkey breeding relies almost entirely on artificial insemination, yet avian sperm are unusually vulnerable to cooling and freezing injury. As a result, extender chemistry and processing steps, especially low-temperature equilibration, are pivotal for post-thaw performance. We evaluated how extender choice, paired with equilibration time, shapes the post-thaw quality of turkey semen. Ejaculates were diluted in Beltsville, Sperm Motility Medium (SMM), Botucrio, or Kobidil⁺, then equilibrated for 20 or 40 min before freezing; samples were cryostored for one month and assessed immediately after thawing. The outcomes included motility/kinematics, membrane integrity, mitochondrial activity and membrane potential, apoptosis/necrosis, reactive oxygen species (ROS), DNA fragmentation, and bacteriological load. Overall, 20 min equilibration improved post-thaw motility and membrane integrity, and reduced DNA fragmentation and ROS. Among extenders, Beltsville delivered the best overall sperm quality. Considering the extender × time interaction, Beltsville, Botucrio, and Kobidil⁺ performed best at 20 min, whereas SMM performed best at 40 min. Thus, Beltsville and SMM provide strong, time-specific options for turkey semen cryopreservation-Beltsville at 20 min and SMM at 40 min.