This study was conducted to investigate optimal time of artificial insemination (AI) to Hanwoo female after natural estrus. AI was occurred 12 and 24 hours after natural estrus in both heifer and multiparous recipient then pregnancy and parturition rates were estimated. Results indicated that AI performed at 24 hours after natural estrus showed significant (p<0.05) higher pregnancy rate in both heifer and multiparous recipient groups with significantly (p<0.05) higher abortion rate. However, there are no significant differences of parturition rate, twin birth and sex ratio in both heifer and multiparous recipient groups. Therefore, our results may suggest that performance of AI at 24 hours after natural estrus promise higher pregnancy rate than AI at 12 hours after natural estrus in both heifer and multiparous recipient.

The objective of this work was to analyze the concentrations of progesterone (P4) and estrogen (E2) hormones changed during estrus synchronization in dairy heifers. Estrus synchronization was carried out with CIDRⓇ (Controlled Intravaginal Drug Release) devices. Corpus luteum (CL) was classified into three grades based on its size and palpable characteristics. The concentrations of P4 and E2 were measured by enzyme-amplified chemiluminescence. Serum P4 concentration was markedly low at the estrus stage (36 hrs after removal of CIDR) compared to other stages, while E2 concentration was kept high during estrus stage. The serum P4 concentration was highest in the CL classified into gradeⅠ. These results indicate that P4 concentration could be used as a criteria for determining recipients for artificial insemination or embryo transfer in dairy cattle.

This study was designed to adopt two estrus synchronization protocols in zebu and crossbred heifers and their effects on pregnancy rate after timed artificial insemination (TAI). A number of 120 cyclic heifers were allotted for two different treatment groups and one control group. Heifers under protocol A were injected with GnRH at first day followed by a single dose of at Day 11 and injection of GnRH at the day of AI; and heifers belonged to protocol B were treated with GnRH, two injections at 11 days apart and injection of GnRH at AI. AI was done at fixed time (within 72~96 hours after injection) in both protocols and pregnancy was confirmed by rectal palpation on 80~120 days of post AI. In control group; local heifers were conceived higher (30%) proportion than that of crossbred heifers (25%; p<0.05). In protocol A, the local breed were conceived higher (38.9%) proportion compared with crossbred (25%; p<0.05). In protocol B, local breed heifers were conceived higher (38.9%) proportion compared with crossbred heifers (33.3%; p<0.05). The overall pregnancy rate in protocol A and protocol B was 33.3% and 36.6%, respectively. The proportion of pregnancy rate of local heifers (38.9%; Protocol A) was significant (p<0.05) in comparison with local heifers (30%) in control group (p<0.05). The overall pregnancy rate between pooled control group (28.3%) and treatment group (35%) was significantly (p<0.05) differ from each other's. Results of present study concluded that estrus synchronization followed by fixed time AI could be applied for higher pregnancy rate in zebu and crossbred heifers.

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.

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.

A study on estrus synchronized dairy cows using progesterone intravaginal device was done to classify each cow's reproductive status from calving to synchronization and to evaluate the reproductive performance according to ovarian and uterine status, and calving season. From calving to estrus synchronization, silent heat or error of estrus detection among ovarian status and endometritis among uterine disorders were exposed in the most distribution (75.4% and 48.3%, respectively). The pregnancy rate of cows with inactive ovaries was lower than those in the follicular and luteal phase. And according to the uterine status before estrus synchronization, the pregnancy rate was similar in three groups; normal, endometritis, and pyometra (70.9, 69.1 and 100%, respectively). The interval from calving to conception was shorter (p<0.05) in cows calved during autumn than in cows calved during spring and winter.

Growth hormone (GH) is obligatory for growth and development. But, there is controversy on the GH effect about reproductive processes of sexual differentiation, pubertal maturation, gonadal steroidogenesis, gametogenesis and ovulation. This study was conducted to investigate the effect of GH on estrus, ovulation and embryo implantation. The results obtained were as follows. GH stimulated to increase estrus rate (p<0.05), pregnancy rate (p<0.05), and total fetus number in mice treated for superovulation. Also, the correlation between GH and steroids, E2 and P4, at peri-estrus stage/ peri-ovulation stage/ peri-implantation stage of the superovulation-induced mice was examined. Consequently, GH co-injected with PMSG especially increased P4 level (p<0.05) at peri-estrus stage of superovulationinduced mice. In conclusion, GH co-treatment in superovulation system boosted the rate of estrus, pregnancy and total fetus by increasing progesterone level at peri-estrus stage of superovulation-induced mice.

Eight female Himalayan tahrs (Hemitragus jemlahicus) were estrus-synchronized, and transcervically inseminated with frozen-thawed semen in September, 2009, about 2 to 3 months earlier than their natural breeding season. Intravaginal progesterone-releasing devices were inserted into vaginas of six Himalayan tahrs on September 7, and the other two on September 8 to suppress luteal function of ovaries. The devices had been placed deep inside the vagina prior to withdrawal on September 23. A day before CIDR removal, a combination of PMSG 400 IU and hCG 200 IU was intramuscularly injected. Forty hours later, frozen-thawed semen was transcervically inseminated. Pregnancy diagnosis was performed 39 days later by analyzing progesterone level of serum. Every treatment was done under anesthesia inducted by xylazine injection. In conclusion, vaginal discharge of cervical mucus, hormonal changes induced by implant-typed or muscularly injectable hormones and widening of cervix enough to insert an insemination gun into uterine body were achieved in non-breeding season. Moreover, the first inseminated Himalayan tahr, 36 hours after CIDR removal was assumed to be pregnant but the fetus may have been lost due to the use of anesthetic drug.

The purpose of this study was to evaluate the effects of days open on subsequent reproductive performance following to estrus synchronization in the 114 lactating dairy cows. The animals were divided into two groups according to the time of estrus synchronization; viz, 85 days, and > 85 days postpartum, respectively. The estrus synchronization protocol consisted of insertion of a controlled internal drug release (CIDR) device containing 1.9 g progesterone with an injection of 250 gonadorelin (Day 0), an injection of and removal of the device on Day 7, an injection of 250 GnRH on Day 9, and TAI 17 h later. Pregnancy diagnosis was determined at 30 to 60 days after TAI using both ultrasonography and rectal palpation. The body condition score (BCS) gradually increased over the postpartum period. In estrus synchronized cows until 85 days, conception rate on first service, number of service per conception, interval from estrus synchronization to conception, and interval from calving to conception were not significantly different among two farms (P>0.05). In estrus synchronized cows after 85 days postpartum, conception rate on first service, number of service per conception and interval from calving to conception were significantly different () between herds A and B (26.8 vs 50.0%; vs times, vs days, respectively). In estrus synchronized cows after 85 days postpartum interval from estrus synchronization to conception was greater (P<0.01) in herd B than in herd A ( vs ). These results indicate that the time of estrus synchronization for maximized the reproductive performance is before 85 days postpartum and feeding and management is important factor for high reproductive performance.

The objective of this work was to determine the effect of corpus luteum (CL) grade on pregnancy rate after embryo transfer in Korean cattle and we found that CL development was linked to pregnancy rate. The in vivo derived blastocyst-stage embryos were transferred to 15 recipients synchronized in the estrus cycles. Based on size and palpable characteristics, CLs were categorized into three grade. The grade three CL is not to be identified by rectal palpation. The pregnancy rates tended to increase with the increase in CL size of recipients. In grade one, two, and three, the pregnancy rates were 62.5%, 50.0%, and 0%, respectively. This result suggests that pregnancy rates after embryo transfer might be affected by the CL status of recipients.

The purpose of this study was to determine the relationship between conception rate and other parameters (body condition score; BCS, progesterone concentrations and follicle size) before estrus induction with CIDR(intravaginal progesterone-releasing controlled internal drug release). The conception rate in cows with < 2.75, 2.75 to 3.25, and 3.25 <, BCS regardless of AI (artificial insemination) time was 46.6%, 63.3%, and 46.6% at CIDR insertion, respectively. The conception rate regardless of BCS was 54.9% in cows inseminated based on detected estrus, and 48.7% in cows inseminated at 72 to 80 hours (timed artificial insemination, TAI) after removal of CIDR. The conception rate regardless of AI time was 40.0% in cows with low progesterone concentrations (less than 1.0 ng/ml), and 56.6% in cows with high progesterone concentrations (more than 1.0 ng/ml) at CIDR injection. The conception rate regardless of progesterone concentrations was 53.8% in cows inseminated based on detected estrus, and 38.0% in cows of TAI after removal of CIDR. The conception rate regardless of AI time was 43.3% in cows with small follicle (less than 5 mm), 53.3% in cows between 5 mm to 10 mm of follicle, and 63.3% in cows with large folliclc (more than 10 mm) at CIDR injection, respectively. The conception rate regardless of follicle size was 58.4% in cows inseminated based on detected estrus, and 45.9% in cows of TAI after removal of CIDR. These results indicated that if the cows with BCS 2.75 to 3.25, active corpus luteum, and/or large dominant follicle (more than 10 mm) are used for estrus induction, the conception rate will be greater.

Four estrus-induced Himalayan tahrs (Hemitragus jemlahicus) were inseminated with frozen-thawed semen by laparoscopic or transcervical insemination techniques with no regard to the site of ovulation in non-breeding season. In June and July, 2009, estrus was synchronized by Eazi-Breed (Controlled internal drug release; Pfizer Animal Health, New Zealand) insertion for 16 days and PG 600 (PMSG 400IU, hCG 200 IU; Intervet, Netherlands) injection (IM) a day before removing . Forty eight hours later, laparoscopic or transcervical insemination was done to each of two tahrs under anesthetic condition inducted by ketamine (1.5 mg/kg) and medetomidine (0.09 mg/kg). For examination of estradiol and progesterone, blood was collected right before insertion, PG 600 injection, removal and insemination. Estradiol levels of four tahrs (No. 1, 2, 3, 4) before insertion and insemination were 13.3, 8.8, 14.3, 12 pg/ml and 23.5, 25.5, 21.1, 11.5 pg/ml, respectively. Progesterone levels of four tahrs (No. 1, 2, 3, 4) before insertion and insemination were 1.8, 0.05, 0.63, 0.61 ng/ml and 1.03, 0.37, 1.48, 2.12 ng/ml. Except for No. 4 tahr, cervices showed cervical mucus and opened enough to penetrate with embryo transfer gun sheet usually used for cows. Therefore, No.4 was laparoscopically inseminated together with No. 1. In conclusion, none of four Himalayan tahrs was pregnant. However, we proved that estrus could be induced by CIDR and PG 600 injection in non-breeding season, and laparoscopic or transcervical insemination with frozen-thawed semen could be one of assisted reproductive techniques in Himalayan Tahr.

On January 6, 2010, two months earlier than normal breeding season, a red fox vixen was implanted with synthetic GnRH analogue, Deslorelin. Blood was sampled every 2~3 days from the day of implant to identifying spermatozoa on stains of epithelial cells. Estradiol and progesterone were examined. Even though the vixen was in non-breeding season, she was mated by a male fox. Pregnancy was confirmed by canine pregnancy detection kit that detect relaxin released from placenta. Four healthy pups were born on March 9, 2010. This is the first report showing synthetic GnRH can activate ovarian function and lead to fertile estrus of red fox in non-breeding season.

The purpose of this study was to determine the relationship between conception rate and other parameters (body condition score; BCS, progesterone concentrations and follicle size) before estrus induction with . The conception rate in cows with (2.75, 2.75 to 3.25 and 3.25), BCS regardless of AI (artificial insemination) time was 47.5, 67.5% and 48.5% at injection, respectively. The conception rate regardless of BCS was 59.0% in cows inseminated based on detected estrus, and 46.2% in cows inseminated at 72 to 80 hours (timed artificial insemination, TAI) after injection. The conception rate regardless of AI time was 43.0% in cows with low progesterone concentrations (less than 1.0 ng/ml), and 67.5% in cows with high progesterone concentrations (more than 1.0 ng/ml) at injection. The conception rate regardless of progesterone concentrations was 59.9% in cows inseminated based on detected estrus, and 48.1% in cows of TAI after injection. The conception rate regardless of AI time was 36.0% in cows with small dominant follicles (less than 5 mm), 56.0% in cows between 5 mm to 10 mm of follicle size, and 65.5% in cows with large dominant follicles (more than 10 mm) at injection, respectively. The conception rate regardless of follicle size was 57.3% in cows inseminated based on detected estrus, and 47.6% in cows of TAI after injection. These results indicated that if the cows with BCS 2.75 to 3.25, active corpus luteum, and/or large dominant follicle (more than 10 mm) are used for estrus induction, the conception rate will be greater.

We report herein the successful results of estrus induction, sperm cryopreservation and kids born by transcervical insemination of frozen-thawed semen in a Saanen goat. Flugestone acetate (FGA: 60 mg) was inserted into vagina for 15 days. The goat was intramuscularly injected with 400 IU PMSG and 200 IU hCG (: Intervet, Korea) a day before withdrawal of the FGA sponge. Follicles and corpora lutea were identified on both ovaries by laparoscopy. Artificial insemination was performed 46 hours after removal of FGA sponge. The concentration of frozen-thawed semen was and 0.5 ml of frozen-thawed semen was transcervically inseminated into uterine body under anesthesia. Three kids, all females, were born 144 days after artificial insemination. This is the first report producing kids by transcervical insemination of frozen-thawed semen in a Saanen goat of which the estrus was induced by FGA sponges, PMSG and hCG during non-breeding season in Korea.