Early detection of Hanwoo cow’s estrus is an important issue in the management of group-housed livestock. In particular, failure to detect estrus in a timely and accurate way can become a limiting factor in achieving efficient reproductive performance. Although a rich variety of methods has been introduced for the detection of estrus, a more accurate and practical method is still required. The behavior of 50 estrus and 100 non estrus Hanwoo cows was video recorded and analysed in 2 Korean native cattle farm. All 50 estrus cattle (100%) showed the mounting or mounted behavior, but only 5 of 100 non estrus cattle (5%) showed the mounting or mounted behavior. One hundred and fifty Hanwoo cows with an age between 2 to 5 years that were expected to come into estrus within 3 days were randomly assigned to each compartment for the estrus group. The heated cows were video recorded for about 24 hours until after post estrus. The results showed that Hanwoo cows can be considered on estrus when it stand immobile during mounted by any other cow in more than or equal to 3.15 s and 3.22 s in chest-tail head mount and head-above back mount and that occurs consecutively at least three times within 876.4 s interval. The algorithm was also developed using the thresholds of the mount duration, mount interval and consecutive occurrence number. The Hanwoo cow’s estrus detection system using IR sensor (CEDSIRS) was composed of IR sensors, a controller, a CPU, a mobile, and so on. If total COUNT numbers per hour was above 1 and it was maintained more than 7 hours, we determined that a cow was in estrus and 16 h past the time from the first estrus detection was regarded as optimum AI time. The 55 of 57 estrus cows (96.5 %) were detected to estrus. Only 5 of 57 cows detected to estrus (8.8%) were decided to weak estrus and 2 of them were not detected. The total conception rate was 85.7%. The estimated price of CEDSIRS is 3,000,000 Won. Therefore, CEDSIRS will improve largely the average conception rate and economic benefits of Hanwoo cow farms.

To investigate the biochemical nature of changes in vaginal physiology during estrus and pregnancy, we examined the cytology and viscosity, and monitored the protein expression profile in vaginal mucus during estrus and pregnancy. The viscosity progressively decreased from estrus to pregnancy. Cell type analysis revealed that white blood cells progressively increased from estrus to pregnancy, while red blood cells progressively decreased during pregnancy. The cornification index (CI) was higher in estrus than in pregnancy. Protein mass spectrumetry identified the presence of ribosome-binding protein 1, GRIP 1 (Glutamate receptor-interacting protein 1)-associated protein 1, DUF729 (Domain of unknown function729) domain-containing protein 1, prolactin precursor, dihydrofolatereductase, and MMP (Matrix metalloprotease)-9 in vaginal mucus. MMP-2 and MMP-9 proteins in the vaginal mucus were active throughout estrus and gestation, as measured by a gelatinase assay, but most abundant in the vaginal mucus on day 0 of estrus. Results from ELISA of MMP-2 and MMP-9 were in accordance with the gelatinase assay. In light of the crucial role of metalloproteinases in extracellular matrix remodeling, the level of MMP-9 in vaginal mucus might be useful as an indicator of estrus and pregnancy to increase the efficiency of reproduction.