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영어

The Jeju Black Cattle (JBC) are a type of traditional Korean native cattle with a characteristic black fur that covers the entire body. Jeju black cattle are smaller than other breeds and their disposition is very calm. The breed’s qualities and genetic uniqueness helped it to be named as a protected, state-designated national monument in 2013. However, they are endangered crisis. Therefore, in vitro fertilization (IVF) technology is needed to preserve these endangered animals and to further improve their traits. In this context, semen analysis is the most commonly used procedure to evaluate male fertility potential in humans and animals. This study was performed on 3 Jeju Black Cattle (JBC) Bulls belonging to Jeju Special Self-Governing Province Promotion Institute. [JBC A, B, C grade]. The freezing medium (20% egg yolk plus 20% triladyl) to a final concentration of 100×106 sperm cells/mL. For sperm cooling, the 0.5 mL plastic straws filled with diluted samples were kept in refrigerator at 4°C for 2 h. They were placed 3 or 7 cm over liquid nitrogen (LN2) vapor for 10 or 30 min and then directly plunged into LN2 for storage. Thawing was done by transferring the frozen straws into water bath at 37°C for 30 sec for analysis. The sperm motility in each group was assessed using the Sperm Analysis Imaging System (SAIS Plus; Medical Supply Co, Ltd., Korea). The sperm vitality in each group was assessed using the eosin-nigrosin stain. The sperm morphology in each group was assessed using the diff-quik kit. The motility was significantly lower in JBC-C frozen-thawing sperm group (35∼65%) than in JBC-C fresh sperm group (98.5%) (p<0.05). The vitality of fresh sperm group (45∼61%) was similar to that of frozen-thawed sperm group (30∼65%). The morphology of fresh sperm group (72∼89%) was similar to that of frozen-thawed sperm group (83∼93%). These results demonstrate that there were similar in sperm quality (vitality and motility) between fresh sperm and frozen-thawed sperm.