Purpose The Jeju black cattle are a type of traditional Korean native cattle with a characteristic black fur that covers the entire body. The Jeju black cattle are rare breed and designated as national natural monuments in 2013. It is necessary to improve reproductive techniques for the preservation and proliferation of Jeju black cattle. Methionine acts as a precursor amino acid for glutathione in protection of cells from oxidative damage, and plays a vital role in detoxification. Low sperm motility causes infertility because when sperm do not have progressive motility, it was unable to reach the ovum. The purpose on this study was to investigate whether intake of L-methionine improves sperm motility and fertility. Materials and Methods 6 Jeju black cattles over 10 years of age are raised in Subtropical Livestock Research Institute, National Institute of Animal Science, RDA. 6 Jeju black cattles was fed with L-methionine with 10g/day during 6 weeks. Semen of Jeju black cattle were collected by artificial vaginal technique. Collected sperm was diluted with AndroMed® extender and cryopreserved in 0.5 ml French straws. Fresh and freeze-thawed sperm viability and motility were evaluated by CASA. Results The viability and progressive motility of fresh spermatozoa(live spermatozoa means: from 74.41% to 80.22%, progressive motility means: from 80.60% to 95.40%) and freeze-thawed spermatozoa(live spermatozoa means: from 51.26% to 62.05%, progressive motility: from 29.68% to 45.44%) incresed after L-methionine ingestion. Conclusion The intake of L-methionine in genetically valuable cattle over 10 years of age seems to be useful for improving sperm function.

Spermatozoa viability can be assessed by microscopy, flow cytometry, and other methods using fluorescent stain. Flow cytometry can be used to examine the morphological and functional characteristics of spermatozoa in a short time. The purpose of this study was to compare the viability of cryopreserved spermatozoa in Jeju black cattle by two dual fluorescent stain methods. Semen of Jeju black cattle raised in Subtropical Livestock Research Institute, National Institute of Animal Science, RDA were collected with artificial vaginal technique. Sperm was diluted with Triladyl®-egg yolk diluent and then was performed cryopreservation.There was no significant difference in viability of spermatozoa according to the two dual fluorescent stain methods. However, when the distribution of spermatozoa according to the staining method was compared, the spermatozoa group stained with 6-CFDA/PI was more clearly distinguished than the spermatozoa group stained with calcein AM/PI.