This study was conducted to analyze the specific genes associated with sex-determination in Korean native cow. The highly organized spermatogenesis requires accurate spatial and temporal regulation of gene expression, which is governed by transcriptional, post-transcriptional, and epigenetic processes. Recently, farmers have been interested in determining the sexual identity of the calves in their farm. We analyzed the sperm of Korean native and Holstein cows, which were supplied from Hanwoo Improvement Center. We evaluated sperm motility and expression of sperm-specific genes after treating semen with both male- and female reagents. Sperm motility in Korean native cows decreased by approximately 10% in the first 30 minutes after treatment with sex-determination reagent. However, sperm motility of Holstein cows decreased to 60-70% after 15 minutes and to 20-30% after 30 minutes. We selected six specific genes expressing in the spermatozoa to analysis the gene expression level. The Real-time PCR results suggest that the selected genes (Gimap4, Tmeff1, Rac2, Abi2, Rac1, and Clu) were highly expressed in the group treated with the male reagent compared to the group treated the female reagent and to the untreated-group (control). In the present study, we suggest that the selected genes play a pivotal role in sex-determination.

본 연구에서 한우를 공란우로 사용하여 OPU 방법으로 가장 더운 계절의 hot season과 선선한 cool season의 두 계절의 차이에 따른 생성된 난포의 수, 난자 회수율, 난자 등급율, 수정율 및 배반포 발달 능력을 분석하여, 두 계절이 공란우의 번식 능력에 미치는 영향에 관하여 조사하였다. 1. 계절의 영향이 OPU 공란우의 난포 생성 수에 미치는 결과는 난포 생성 개수는 1154개(18.32±2.26), 971개(15.41±3.34)로 hot season 그룹이 유의적으로 높은 것을 알 수 있었다(p＜0.05). 2. 계절에 따른 난자 수 및 난자 회수율은 hot season 그룹의 475개(7.54±3.14), 41.16%로 cool season 그룹 448개(7.11±3.42), 46.14%와 비교하여 유의적인 차이가 없었다(p＜0.05). 3. OPU를 통하여 회수된 두 계절별 난자 등급은 Grade A는 Hot season 그룹 110개(1.75±1.86), Cool season 그룹 63개(1.00±1.46)로 hot season 그룹이 cool season 그룹과 비교하여 유의적으로 높았다(p＜0.05). 하지만 다른 등급인 Grade B는 87개(1.38±1.60) vs. 97개(1.54±1.39), Grade C는 166개(2.63±2.43) vs. 170개(2.70±2.04), Grade D는 112개(1.78±2.65) vs. 118개(1.87±1.86)로 hot season과 cool season 간의 유의적인 차이를 보이지 않았다(p＜0.05). 4. 계절에 따른 체외 수정 후의 수정률은 hot season과 cool season 각각 242(66.67%)와 209(63.3%), 배반포 발달율 214(58.95%) vs. 188(56.97%)로 수정률과 배반포 발달율은 유의적인 차이가 없었다(p＜0.05). 본 연구의 결과로 계절에 따른 영향에 의해 공란우의 난포생성수와 A등급의 난자 출현율에서 유의적인 차이를 보였다. 하지만 나머지 등급의 난자 출현율, 수정률 및 배반포 발달율은 차이가 없는 것으로 보아, 계절의 차이로 인한 한우 공란우의 번식 능력에 미치는 영향은 미비하다고 판단된다.

This study was carried out to investigate the influence of artificial insemination (AI) failure in 1,619 Korean native cows at Gangwon East area, Korea. The average AI failure rate was 37.02% in the cows and the highest rate was 40.85% in Yangyang-city. Based on the parity in the cows, the AI failure rate was 49.14% and 29.91% in the first and fifth parity cows, respectively. Whereas cows until fifth parity were decreased in AI failure, cows with sixth or more parity showed an upturning AI failure trends with the increasing of parity number. AI failure rate incidence according to the rump fat thickness measured by ultrasound was 28.9% and 33.4% at 5 mm to 10 mm and over than 15 mm, respectively. There was a positive correlation (0.2186) between AI failure rate of mother and that of their offspring cows. That is, offspring of dams with high AI failure rate showed also higher AI failure than those of dams having lower AI failure rate. In conclusion, these results indicate that the AI failure rate was closely related to the rump fat thickness, parity number, and conception rate of mother cows. In addition, these results might strengthen the basis to improve the reproductive performance in Korean native cows.

Bovine brucellosis causes abortion and infertility. The authors conducted this study in order to determine pathological lesions of Korean native cows and fetuses who received experimental vaccination with Brucella abortus RB51 and were challenged with Brucella abortus 2308. Gross and histopathological lesions in endometrium and placenta were observed in cows of the vaccinated group. Twenty-five percent of pregnant cattle in the vaccinated group showed endometritis and placentitis, which was three times lower, compared with the non-vaccinated group. The pathological lesions in the uterus and placenta in both groups were consistent with previous reports. Therefore, vaccination in heifers using Brucella abortus RB51 may not provide adequate protection against infection with Brucella abortus virulent strain.

This study was operated to establish induction using ultrasonography by estimating the relation of follicle size and estrus manifestation. Clinical estrus symptoms were observed 97.4% in cows and 87.5% in heifers when overall 55 cows were induced to estrus in a single dose of after verifying CL through ultrasonography, which means estrus hours among those 52 cows showing the clinical estrus symptoms were estimated 2.39 days on cows and for 2.37 days on heifers which showed no differences (p>0.05). The estrus manifestation hours according to the follicle size in cows didn't have any significance each other (p>0.05), though estrus hours was 54 hours (the shortest) with follicle size bigger than 10 mm and were made up within 69 hours. The estrus manifestation hours according to the follicle size in heifers didn't have any significance each other (p>0.05) and took around 42 hours (the shortest) with follicle size of 5mm (the smallest) and were made up within 66 hours. Follicles after injection were ovulated and assigned to many phases as follows; Group 1 (growing phase) - continuously growing into ovulation, Group 2 (growing and static phase) - delaying in growth after the growth of follicles, Group 3 (static and growing phase) - growing after growth delay, Group 4 (regressing and new growing phase) - the follicle is closed and a new follicle grows. In addition, the process of follicle development and estrus hours had no significance each other (p>0.05), though estrus manifestation hours in Group 1 and 2 was relatively short, and in Group 3 and 4 for a relatively long time. In the result of all above, the estrus manifestation hours after injection has no differences accoring to the follicle size in cows and heifers. Therefore, High pregnancy rate is obtained when practicing artificial insemination within 3 days in estrus or TAI in 72 to 80 hours after adminitrating .

This study was carried out to develop the useful inducing method of estrus for Korean native cows. Under the condition of estrus induction by administering for the cows in which corpus luteum (CL) in ovaries was detected by ultrasonography, ovarian responses and the changes of progesterone () concentration against compared with conception rate were observed in cows and heifers. In inducing estrus administering . to the cows which has corpus luteum in ovaries, ovarian reponses, the changes of progesterone concentration, and conception rate were identified and compared. The results attained from the studies were as follows. Significant decreases of CL in size over time after administration were detected in both cow and heifer groups (p<0.001), but not different between groups in the CL regression rate (p>0.05). In addition, the percentage changes relative to the plasma concentration on day 1 after treatment were decreased to below 1ng/ml. The growth rate of follicle was observed as 31% on day 1 and 42% on day 2 in cows, and 34% on day 1 and 97% on day 2 in heifers, resulting that growth of heifers are faster than that of cows (p<0.05). The conception rate after treatment were 60.5% and 64.2% in cows and heifers, respectively. It also indicated that the conception rate after estrus observation with injection was as high as 66.6% while that with timed-artificial insemination (TAI) regardless of the estrus observation was 56%, which means the pregnancy rate of artificial insemination after estrus observation was higher than that of TAI (p<0.05). In the result of all above, there were significant decreases in CL size and the plasma concentration by days but rapid growth in follicles, which has no differences in cows and heifers. The conception rate was commonly high after estrus observation and more than 50% under TAI.

The aim of this study was to evaluate the effect of α-tocopherol on blastocysts development and subsequent cryosurvival of the vitrification. The α-tocopherol(0, 100, 200, 400 μM) was added in to culture medium for the bovine embryos. The blasocysts from the α-tocopherol and untreated control groups were then frozen-thawed, and their cryosurvival was assessed by in vitro culture for 48 h. There were no differences in the overall cleavage rate(56.14±4.66, 58.18±4.70, 62.97±6.86 and 51.17±7.28) among four treatment groups. However, in blastocyst development and total cell number were significantly higher in α-tocopherol 200 μM(38.60±7.12; 106.33±3.50) to culture medium than other treatment groups(29.30±5.24, 31.60±7.12 and 26.37±4.18; 101.36±5.12, 97.27±2.87, and 91.23±7.52 respectively). Before and after vitrification, the total cell number and blastocyst development of embryo were significantly higher in July to August than September to October. In conclusion, addition of α-tocopherol 200 μM to in vitro bovine embryo culture medium was beneficial for improving embryo quality by decreasing the embryo damage blsstocysts cell number and improving the tolerance of the embryos to cryopreservation.

Luteal cells produce progesterone that supports pregnancy. Steroidogenesis requires coordination of the anabolic and catabolic pathways of lipid metabolism. In the present study, the corpus luteum (CL) in early pregnancy established from luteal phase and pregnant phase was analyzed. The first study determined progesterone changes in the bovine CL at day 19 (early maternal recognition period) and day 90 in mid-pregnancy and compared them to the CL from day 12 of the estrous cycle. CL alternation was tested using two-dimensional polyacrylamide gel electrophoresis (2-DE) and matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI- TOF). Comparing CL from luteal phase to those from pregnant phase counterparts, significant changes in expression level were found in 23 proteins. Of these proteins 17 were not expressed in pregnant phase CL but expressed in luteal phase counterpart, whereas, the expression of the other 6 proteins was limited only in pregnant phase CL. Among these proteins, vimentin is considered to be involved in regulation of post-implantation development. In particular, vimentin may be used as marker for CL development during pregnancy because the expression level changed considerably in pregnant phase CL tissue compared with its luteal phase counterpart. Data from 2-DE suggest that protein expression was disorientated in mid pregnancy from luteal phase, but these changes was regulated with progression of pregnancy. These findings demonstrate CL development during mid-pregnancy from luteal phase and suggest that alternations of specific CL protein expression may be involved in maintenance of pregnancy.

The increase in the total number of cows on farms, which breed Korean Native Cattle (KNC), is associated with many problems. In particular, the services per conception and calving interval have increased. In this study, we examined the effect of dietary supplementation with vitamin and mineral complex on the estrus rate, pregnancy rate, gestation length, and birth weight of KNC calves. Multiparous or primiparous KNC were divided into 3 groups with 40 heads per group. Experimental group 1 was administered a consisting of 35,000 IU vitamin A, 100 IU vitamin E, 200 mg -carotene, 200 mg Zn methionine, and 1.5 mg Se. Experimental group 2 was administered a vitamin complex (100 g/day) consisting of 100 IU vitamin E and 200 mg -carotene. In the case of multiparous KNC, the estrus detection rate in the control group was 90.0% and those in the experimental groups were 75.0% to 95.0%. However, the first-service pregnancy rate after parturition in the control group was 41.2%, which was significantly lower than that in the experimental groups (71.0% to 76.7%; p<0.05). The average duration of pregnancy in the group supplemented with the vitamin complex was days, which was similar to that in the case of the control group. The birth weight of calves from cows fed with vitamin complex was 25.3 to 27.0 kg, which was similar to that in the case of the control group (25.2 to 26.0 kg). In the case of primiparous KNC, no differences in the estrus rate, pregnancy rate, gestation length, or the birth weight of calves were noted between the groups. Thus, dietary supplementation vitamin and mineral complex have no effect on the reproductive efficiency in primiparous cows, but the pregnancy rate was observed to have increased in multiparous KNC with these supplements.

The purpose of this study was to determine the effect of cows parity and calving seasons on the subsequent reproductive performance of the herd of Korean native cows raised under the same condition. With the parity of the cows ranged 1 to 4 (mean: 1.9), significant associations were found between parity and calving interval (p<0.05). Calving interval of the primiparous cows group was 395.0 16.5 days, which was the longest calving interval among the four groups. On the other hand, calving interval of the second parity group was 333.7 3.6 days. The primiparous cows had tendencies that long interval from calving to conception and small number of service per conception relatively when compared with the multiparous cows. In the case of calving season, the interval from calving to first service was short in summer and winter relatively. The interval from calving to conception in summer was the shortest in four seasons. The number of service per conception was larger in spring and winter and smaller in summer and autumn. Calving in spring showed delayed reproductive performance and calving in summer showed desirable reproductive performance.

도축장에서 도축된 한우 중 난소낭종에 이환된 소 86두를 대상으로 수침법으로 초음파 검사를 실시하여 낭종의 직경, 낭종내강의 직경, 낭종벽의 두께를 측정하였으며 낭종액 중 농도와 농도를 측정하여 다음과 같은 결과를 얻었다. 난소낭종에 이환된 소 86두는 해부학적 및 초음파 검사에 의하여 단포성 난포낭종 51두(59.3%), 다포성 난포낭종 19두(22.1%), 단포성 황체낭종 13두(15.1%), 다포성 황체낭종 3두(3.5%)의 발생률을 나타내어 황체

To investigate fatty acid constituents and relative compositions in the fluid of the follicles, oviducts, uterine body and uterine body in Korean native cow, the fluids of the reproductive tract were analyzed using gas chromatography. The samples were taken from various reproductive tract of 23 Korean native cows. q. Caprylic acid (C8:0), myristic acid(C14:0), palmitic acid(C16:0), palmitoleic acid(C16:1), stearic acid(C18:0), oleic acid(C18:1), linoleic acid(C18:2), arachidonic acid(C20:4) were found in the reproductive tracts of the cows, which made 8 kinds of fatty acid in total. 2. Palmitic acid, oleic acid, stearic acid were predominant with 35.67%, 24.98% and 17.52%, respectively. while low levels of fatty acids(<5%) were myristic acid, palmitoleic acid and caprylic acid with 1.75%, 1.28% and 2.69%, respectively. 3. Two kinds of polyunsaturated fatty acids, linoleic acid arachidonic acid were found in the reproductive tracts of cows. 4. Palmitic acid among saturated fatty acids and oleic acid among unsaturated fatty acids were the highest level in all of the reproductive tracts. 5. The Highest level of arachidonic acid was found in the uterine horn. 6. The sum of the palmitic acid and oleic acid were 61.72%, 63.72%, 57.66% and 57.65% for the fluid of follicle, oviduct, uterine horn and uterine body of the cows, respectively. 7. The relative compositions of palmitic acid, palmitoleic acid and caprylic acid were higher during the luteal phase than during the follicular phase. 8. The relative compositions of arachidonic acid was higher during the follicular phase in the fluid of uterine horn and uterine body of the cows. 9. The long chain fatty acid, the palmitic acid, stearic acid, oleic acid and linoleic acidshowed higher relative compositions during the follicular phase(86.49%∼95.51%) than during the luteal phase(85.64%∼88.93%).

The present study was carried out for the comparative study on the collection of bovine follicular oocytes by ultrasound-guided ovum pick-up(OPU) and slaughterhouse-derived (SHD) ovary aspiration and in vitro production of bovine embryos with the follicular oncytes in Korean native cows. Bovine follicular nocytes were observed with a 6.5 MHz convex-array ultrasound transducer designed for intravaginal use and the oocytes were collected with the aspiration equipment attached to the ultrasonograph. Bovine ovaries were collected and transported in phosphate buffered saline from the local slaughterhouse, the follicular oocytes were collected by the aspiration method. The collected follicular oocytes in good quality were matured, fertilized and cultured in the media. The total number of the visible follicles and the recovery rate of follicular oocytes were increased in ultrasonography following follicle stimulating hormone(FSH) treatment in Korean native cows. The mean recovery rate of oocytes was 66.2, 52.8 and 41.7% in the FSH-OPU, non-treatment-OPU and SHD ovaries, respectively. The mean number of recorved oocytes per cow were not significantly(P<0.05) different between the FSH-OPU(14.011.54) and SHD(17.1i6.21) groups, but the numbers in both groups were significantly(P<0.05) higher than the number in the non-treatment-OPU(3.71.57) group. The mean number of usable nocytes in Grade T /11 per ovary was 6.3, 4.8 and 1.3 in the cows of the SHD, FSH-OPU and non-treatment-OPU groups, respectively. The in vitro developmental rate to the blastocyst was not significantly different between the oocytes obtained via OPU(37.1%) and SHD(29.3%). Therefore, the ultrasound-guided OPU technique can be applied to the production of excellent embryos from the high-quality cows, and for the large scale production of in vitro bovine oocytes and embryos, the SHD ovary aspiration method is valuable.

This study was carried out to compare the actual size(length and height) of ovaries, follicles and corpora lutea of Korean native cow with those on sonograms. We used 3 different probes(3.5 MHz abdominal probe, 6.5 MHz transvaginal probe and 5.0 MHz transrectal probe) and a calipher for measurements of ovaries, follicles and corpora lutea on sonograms and actual size. Under water immersion, 157 ovaries were scanned with 3 probes and measured in actual size and compared each other. The average height and width of ovaries of Korean native cows were 17.403.99 and 34.236.02mm, respectively. In comparison of height, length of ovaries and preovulation follicles, we found that image with a transvaginal probe was nearly the same as the actual size(p<0.01), but with an abdominal probe the image was appeared larger than the actual size. In measurement(diameter) of preovulation follicles the transvaginal probe was proven to be more accurate to the actual size than other probes and in corpus luteum measurement all probes were accurate. In the comparison of number of follicles by different size ranges, there was no statistical difference in the count of follicles over 10 mm in diameter between the transvaginal probe and naked eyes.