Ensuring timely ovulation concerning the service is valuable. A satisfactory conception rate can be achieved by making sure that ovulation occurs within 7-18 hours after artificial insemination (AI). Delayed ovulation is one of the disturbances commonly encountered in repeat breeding animals. Although demanding research, many studies have not been conducted. Therefore, we aimed to examine the relation between ovulation confirmation and conception rate in dairy cattle. The research findings showed that the signs of true estrus were bred 12 hours after the onset of estrus by AI in cattle. Also, the performance of AI on ovulation was confirmed by the presence of fluctuant Graafian follicles through rectal palpation. From the results, we confirmed that cow encountered delayed ovulation were bred again. The Conception rate in cows with confirmed ovulation was 51.9%, while for those without confirmed ovulation were 33.3%. In conclusion, the results indicate that ovulation confirmation will likely increase conception rate.

Abstract
 INTRODUCTION
 MATERIALS AND METHODS
 RESULT
 DISCUSSION
 REFERENCES

• Hyun-Joo Lim(Dairy Science Division, National Institute of Animal Science, RDA) Correspondence
• Ho-Beak Yoon(Dairy Science Division, National Institute of Animal Science, RDA)