The purpose of this study was to examine the effect of growing stages of the Korean Native Striped Bull (KNSB) on the freezability and fertility of frozen-thawed semen. First, we investigated the total motility (TM) and progressive motility (PM) according to the diluent used for semen freezing. Second, we examined the effect of the age of KNSB on semen volume, TM and PM of fresh and frozen-thawed semen. Third, we examined the effect of frozen semen from the different age of KNSB on the fertilization rate, and the artificial insemination pregnancy rate. The diluents used in this experiment were Triladyl and Tris-egg yolk extender (EYE). Semen was collected from 5 KNSB in the growing stage (15 months) and 5 adult KNSB (36 months). When Triladyl or Tris-EYE extender was used for semen freezing, there was no difference of the mean TM and the mean PM. However, the mean TM was significantly higher in Bull No. 1885 than Bull No. 4283 ( <0.05). The mean volume of semen collected from the 15-month-old bulls (2.3 ml) was significantly lower ( <0.05) than that from the 36-month-old bulls (5.0 ml). The mean semen concentration was similar for the 15-month-old ( spermatozoa/ml) and 36-month-old ( spermatozoa/ml) bulls. For the 15-month-old and 36-month-old bulls, the mean TM of fresh semen were 93.7% and 88.3%, respectively, and the mean PM were 97.0% and 88.3%, respectively; the 15-month-old bulls showed a particularly high PM ( <0.05). For the 15-month-old and 36-month-old bulls, the mean TM (56.0% and 58.0%, respectively) and the mean PM (64.0% and 70.7%, respectively) of frozen-thawed semen did not differ. The development rates of embryos after fertilization and the pregnancy rate after artificial insemination using frozen-thawed semen did not differ according to the bull's age. In summary, semen volume differed according to the bull's age, but semen concentration and survival rate, the fertilization rate, and the pregnancy rate did not differ according to the stripe bull's age. Accordingly, semen from bulls in the growing stage can be collected and frozen for the preservation and multiplication of rare livestock.

국외에서 승용말 번식에서 인공수정 및 수정란이식의 활용도가 높지만, 국내에서 사육 되는 말은 대부분이 경주마로 자연종부로만 번식을 하고 있다. 인공수정 등 번식기술의 국산화를 위해서는 발정주기의 난포 변화와 난포 변화에 따른 호르몬 변화 등의 연구가 필요하다. 본 연구에서는 말 발정기의 난포크기에 따른 프로제스테론과 에스트로젠의 변 화 및 난포 크기에 따른 배란유도와 인공수정 결과를 조사하였다. 말의 난포 크기가 발정증상 개시부터 2 cm, 3 cm 및 4 cm 이상에서 혈액내 프로제스 테론과 에스트로젠을 분석하였다. 발정개시 후 난포의 크기에 따라 hCG를 이용 배란을 유도하였고, 배란 유도 후 24 및 40시간에 동결정액으로 2회 인공수정 하였다. 발정기의 말에서 혈액내 프로제스테론 농도는 난포의 크기가 각각 2 cm, 3 cm 및 4 cm에서 평균 9.09 ng/ml, 13.04 ng.ml 및 1.40 ng/ml로서 4 cm에서 급격하게 감소하였 다. 한편 에스트로젠농도는 각각 평균 59.20 pg/ml, 48.5 pg/ml, 및 41.07 pg/ml로서 차이 가 없었다. 배란유도 시점의 난포 크기가 임신율에 미치는 영향을 조사한 결과 난포 크 기가 4 cm 미만에서는 임신율이 0%였으나, 4 cm 이상에서는 60%였다. 배란유도 후 인 공수정 시점의 난포 크기가 임신율에 미치는 효과를 조사한 결과 난포 크기가 5 cm 미 만은 임신에 실패하였으나, 5 cm 이상에서 60%의 임신율을 나타냈다. 본 연구를 통하여 발정기 말의 배란유도 및 인공수정 시점에 주기적인 초음파 검사를 통한 난포 크기의 확인이 인공수정의 임신율에 영향을 미치는 것으로 판단된다.

Research in the area of equine artificial insemination (AI) has led to its increased application in field trials. However, procedures for equine semen collection, cooling and freezing of semen and artificial insemination need further improvement. In experiment 1, we investigated the percentage of total motility (TM) and progressive motility (PM) of sperms at after-collection, cooled-diluted, cooled-transported or frozen-thawed semen. In experiment 2, mares were inseminated with either cooled-diluted, cooled-transported or frozen-thawed semen. In experiment 3, we examined the effect of buffer (skim-milk extender), which was infused into the uterus at the time of AI with frozen-thawed semen. In experiment 4, we compared AI pregnancy rates for mares ovulating spontaneously versus after treatment with hCG. In experiment 1, the average percentage of TM was decreased from 75.3% to 14.4% at the stage of after-collection to frozen-thawed semen (p<0.05). The average percentage of PM was 58.2% and 59.6% at after-collection and cooled-diluted, but it was significantly increased 71.7% after frozen-thawed (p<0.05). In experiment 2, the pregnancy rates after AI using cooled-diluted, cooled-transported and frozen-thawed semen were 60%, 50% and 37.5%, respectively, and similar among treatments. In experiment 3, the pregnancy rate of mares infused with buffer at AI was 40% which was higher than that with no buffer (10%). In experiment 4, the pregnancy rates of mares were similar between ovulated spontaneously (25%) and ovulated with hCG (50%). The results suggest that equine semen that has been cooled-diluted, cooled-transported or frozen can be successfully used to establish AI, pregnancy and foal production. Also, the pregnancy rates after AI can be increased by infusing buffer into the uterus at AI or by inducing ovulation with hCG, but further study is need.

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 present study investigated the efficient methods to produce in vitro Hanwoo embryos, and to improve the pregnancy rate. The developmental rate, total cell number and ICM ratio of in vitro embryos were compared amongst different culture media. Comparisons were also made on the status of recipients, pregnancy rate along with day of transfer after the estrus. Development of embryos into blastocyst stage in IVMD101 supplemented with 5% fetal bovine serum (FBS) group was significantly higher (34.2%) than that of TCM-199 supplemented with 5% FBS (26.8%) and IVMD101 without FBS (25.9%) (p<0.05). The development rate to blastocyst stage was significantly faster in IVMD101(5% FBS) than that of other groups () (p<0.05). The average number of inner cell mass and trophectoderm were similar among treatment groups, which were and . However, total cell number in IVMD101(5% FBS and 0% FBS) was significantly higher than that of TCM199(5% FBS). There were no differences in the pregnancy rate among treatment groups (32.0%, 33.9% and 28.6%, respectively). However, the pregnancy rate of Day 6 embryos cultured in IVMD101(5% FBS) was significantly (p<0.01) higher than IVMD101 without FBS and TCM-199 + 5% FBS (38.0% vs. 17.2% and 32.4%, respectively). No significant difference was observed for the pregnancy rate between heifer and cow transferred with Day 6 embryos cultured in IVMD 101(5% FBS) (42.7% and 39.3%, respectively). However, there was a significant difference of pregnancy rate (p<0.05) in heifer between one and two embryos transferred (31.4% and 41.9%). There was no difference of pregnancy rate among transfer days after estrus between heifer and cow, but the pregnancy rate of transfer to heifer with day 6 after estrus was significantly higher (p<0.05) than that of day 7 and 8 (22.2% vs. 49.0% and 38.7% respectively). Based on the above findings, there is a possibility to produce in vitro produced embryos cultured in IVMD101(5% FBS) showed higher blastocyst rate and the increased cell number. In terms of the pregnancy rate of in vitro produced embryos, the highest pregnancy rate was observed when two embryos were cultured in IVMD101(5% FBS) and transferred.

본 연구는 개 채취 정액의 동결후의 생존성과 신선 및 동결 정자의 capacitation, acrosome reaction과 생존성을 조사하고, 아울러 신선 및 동결 정액을 자연 발정 또는 발정 유기 암캐 에게 인공수정 후 임신율을 조사하였다. 개 채취 정액의 동결 융해 후의 생존성은 로서 신선 정액의 생존성에 비해 유의하게 낮게 나타났다(p<0.05). 신선 및 동결 정액의 capacitation, acrosome reaction 및 생존성은 각각 및

무발정 증상을 보이는 젖소 65두를 대상으로 몇 가지 호르몬 처리기법을 사용하여 소의 번식효율 향상시키고자 본 실험을 수행하였다. Group 1. Ovsynch program (GnRH-PGF a /PGF a/GnRH), Group 2. Two plus Two program (GnRH-PGF a /PGF a/GnRH), Group 3. progesterone implant (CIDR)-GnRH/PGF a/PGF a/GnRH과 Group 4. (Folli

This study was undertaken to test the hypothesis the hypothesis that treatment with hCG (5,000 IU) at the time of embryo transfer would enhance pregnancy rates in recipients, and the concentration of plasma urea nitrogen(PUN) in recipients was related to the effect of hCG on the reproductive performance. Blood samples were taken according to experimental condition for the assessment of the endogenous plasma progesterone concentration and plasma urea nitrogen. Concentrations of progesterone in plasma were higher in cows treated with hCG on day 7(estrus=day 0) than in those untreated during 7∼43 days after insemination. The pregnancy rates were 65.5 and 54.6% for the hCG treated and untreated groups, respectively. In recipient group categorized with PUN concentration of <12 mg/이, the pregnancy rates were 68.8 and 46.7% for the hCG treated and untreated groups, respectively. The results suggest that hCG treatment at 7 days after insemination could be used to increase the pregnancy rate of embryo transfer, and transfer, and only the recipients with PUN concentration of <12 mg/dl were influenced by treatment with hCG.

It is widely recognized that the embryonic or fetal loss after breeding is common in the cattle and that it is an important factor affecting reproductive efficiency. The causes of this loss have been subject of extensive researches and the results indicate that the embryonic mortality may he primary factor responsible for low pregnancy rates in non-embryo transfer bovine populations as well as embryo transfer programs. However, it's causes are still not clearly understood. The embryonic mortality or pregnancy rate has been influenced by various embryonic and maternal effects related to genetic and environmental factors. The timing and extent of embryonic mortality vanes greatly according to authors and estimating methods, because it is difficult to make direct measurements. The major important factors that may influence the embryonic losses or pregnancy rates after embryo transfer can be summeirized. 1.When an embryo is transferred to unmated recipients, the contralateral transfer to corpus luteum results in a lower survival rate than ipsilateral deposition. When the embryos are transferred for the production of twin calves, their survivals and twin pregnancies have quite inconsistent according to the transfer methods either to the unmated-synchronized or already mated recipients and more works are needed to accurrately clarify the previous results. 2.Although embryos can be cultured in vitro some hours without the great declines in pregnancy rates, the rates differ markedly among culture times and media but may be improved by co-transfer systems. 3.Embryo developmental stages and quality grades clearly affect the survival rate following freezing and the pregnancy rate after transfer and the selection of embryos without chromosome abnormalities and of high fertile semen may also be considered to increase the pregnancy rates. 4.Many researches have attempted to relate the plasma progesterone levels to pregnancy rates and others have done either direct progesterone supplementation or luteal stimulation by hCG treatment in order to increase the pregnancy rates. However, these effects on pregnancy rates are inconsistent and also contradictory. 5.The asynchrony between donors or embryos and recipients may he a major cause of embryo death and low pregnancy rate and the sensitivity to uterine asynchyony differs in according to the quality and stages of embryos. 6.The extremes of poor or over nutrition during early pregnancy in the recipients are detrimental to the survival of embryos and the good body condition is required to prevent a reduejion of pregnancy rates. The uterine pathogens in embryonic mortality or fertility have been questioned but the infection of C.pyogenes and Campylobacter fetus is still important pathogens. 7.The heat stress during early pregnancy may reduce conceptus weight and possibly increase the embryonic mortality.