Artificial insemination with liquid-stored and fresh semen in grey partridge (Perdix perdix L.)

European populations of the grey partridge (Perdix perdix L.) have declined rapidly, necessitating captive breeding programs to supplement wild populations. Artificial insemination could optimize these reproductive efforts, yet specific protocols are lacking. This study evaluated the effects of short-term liquid storage (24 h at 5 °C in EK and Lake extenders) on selected semen quality parameters and determined how extender type and sperm dose affects fertility level. Semen was collected from 15 males, pooled, diluted 1:2 and evaluated in vitro at 0 h and after 24 h of storage. Sperm motility and kinematics were assessed using Sperm Class Analysis system, whereas viability and morphology were evaluated by nigrosin-eosin staining. Obtained data was analyzed using repeated measures ANOVA. Fertilization outcomes, assessed by incubating eggs laid following artificial insemination, were analyzed using generalized linear mixed models. Storage significantly reduced sperm motility, viability and the proportion of morphologically normal spermatozoa (P < 0.05). The EK extender better preserved sperm viability and normal morphology, whereas the Lake extender maintained a more stable kinetic profile over the time. Fresh ejaculates naturally exhibited a remarkably low proportion of morphologically normal spermatozoa (14.2%). In vivo, sperm dose significantly affected fertilization success (P < 0.05); with higher doses (≥ 16 × 10⁶ spermatozoa) consistently resulting in higher fertility rates in both fresh and stored semen. Extender type did not significantly affect fertilization rates. Progressive motility showed a tendency to predict fertilization success after storage (P = 0.06). Despite reduced in vitro semen quality, short-term liquid storage of grey partridge semen can be effectively applied in artificial insemination procedures when an adequate sperm dose is used. These findings provide a practical basis for improving reproductive management and developing genetic resource conservation strategies in this species.