Abstract: To explore the ultrastructure changes of dairy goat spermatozoa during liquid storage at 4℃, and provide a morphological basis for elucidating the relevant mechanisms that affect the quality of dairy goat spermatozoa during liquid storage. The semen of Guanzhong dairy goats was collected and stored in a liquid state at 4℃, sperm viability at 0, 24, 48, 72, 96, 120 and 144 h of storage was detected by eosin staining, the ultrastructure of spermatozoa at 0, 48, and 96 h was observed by scanning electron microscope and transmission electron microscope. The results of eosin staining showed that sperm viability gradually decreased with the prolongation of liquid storage time. The ultrastructure showed that at 0 h, the sperm morphology and structure were normal, the acrosome was intact and smooth, the mitochondrial sheath of sperm tail were intact, and the mitochondria were arranged regularly, and the morphology and size were normal; at 48 h, some spermatozoa showed structural damage such as tail breakage and curling, nuclear membrane expansion and folding, and mitochondrial swelling; at 96 h, some spermatozoa suffered damages such as acrosome damage, main segment fracture, nuclear disintegration and fragmentation, mitochondrial deletion and disordered arrangement. At 48 and 96 h, some spermatozoa exhibited typical apoptotic morphological features, such as needle-like protrusions on the nuclear surface, cystic vacuoles and apoptotic bodies. The above results showed that during the liquid storage at 4℃, the sperm of dairy goats suffered structural damage, some spermatozoa had typical apoptotic morphological characteristics, sperm viability decreased gradually, suggesting that the sperm structure damage of dairy goats led to the decrease of viability.

Key words: dairy goat, spermatozoa, 4℃ liquid storage, ultrastructure