• Journal of Animal Reproduction and Biotechnology
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• v.35 no.2
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• pp.183-189
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• 2020

The pregnancy rate in indigenous ewes inseminated with frozen-thawed Suffolk semen following natural and synchronized estrus was determined. The serum Progesterone and Estrogen concentration and vaginal electrical resistance (VER) of ewes at the time of Artificial Insemination (AI) were observed as successful pregnancy determinants. 21 healthy ewes were selected for this experiment during January-April, 2017. 10 ewes were inseminated in natural estrus. Whereas, 11 ewes were inseminated after estrus synchronization using intravaginal sponges containing 60 mg medroxyprogesterone acetate. Trans-cervical Al (TCAI) was performed in all ewes within 12-16 hours of observed heat. Prostaglandin E₁ analogue impregnated vaginal sponge was used for cervical relaxation 6-8 hours before insemination. Pregnancy was diagnosed through trans-abdominal ultrasonography after 40 days of AI. The pregnancy rate of ewes in synchronized estrus was higher (54.5%) than in natural estrus (30%). Higher serum Progesterone level (0.90 ± 0.02 ng/mL) and significantly (p < 0.001) lower VER (257.78 ± 10.11 ohm) were observed at the time of AI in ewes becoming pregnant. Results suggest that higher Progesterone concentration and lower VER could be considered as pregnancy indicators. Oestrous synchronization could be implemented to increase the pregnancy rate in ewes.

• Journal of Embryo Transfer
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• v.24 no.4
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• pp.271-274
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• 2009

To establish a protocol of estrus induction and synchronization in European mouflon, we performed artificial insemination using frozen-thawed semen and exogenous hormones. CIDR was inserted into vaginas of four mouflons for 16 days. A day before removal of CIDR, PG 600 was injected intramuscularly. $PGF_2{\alpha}$ was injected when removing CIDR. Artificial insemination was cervically conducted with injecting LHRH 48 hours after CIDR withdrawal. Even though no pregnancy was confirmed, estrous signs were notified like open cervix, congestion of vaginal wall and discharge of cervical mucus. Further research in the wild sheep would be needed for development of artificial breeding methods and advancing sustainability of domestic zoos.

• Journal of Embryo Transfer
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• v.20 no.3
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• pp.297-302
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• 2005

Artificial insemination (AI) technology has widely applied in domestic animals including cattle for production and preservation of valuable animals. However, AI in goat was poorly studied. We here compared two different estrus synchronization methods, CIDR (controlled intravaginal drug release)+$PGF_2a$ and CIDR+PMSG, in Korean native goats. After treatment of CIDR+$PGF_2a$ or CIDR+PMSG for estrus synchronization, AI was applied to 38 recipients. Of 18 recipients treated with CIDR+$PGF_2a$, 4 recipients produced offsprings. However, no pregnancy was obtained in 20 recipients treated with CIDR+PMSG. Especially, after treatment of CIDR+$PGF_2a$, AI with fresh or frozen sperm showed markedly higher parturition rates than that of CIDR+PMSG. From these results, we suggest that combination of CIDR and $PGF_2a$ could be used as good method for estrus synchronization in Korean native goats.

• Korean Journal of Animal Reproduction
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• v.1 no.1
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• pp.65-72
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• 1977

• Proceedings of the KSAR Conference
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• 2001.03a
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• pp.53-53
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• 2001

Two trials were conducted in a commercial dairy farm on heifer synchronization with PGF$_2$ $\alpha$. Animals showing estrus following the first injection were bred and animals not showing estrus were given the second injection 10 days later. In the first trial, the injection sites were rump and rump. In the second trial, the injection sites were rump and shoulder. Estrous detection was peformed 24 h after injection. Animals were bred by the same technician. In the first trial, the response rate for the first injection was 51.4% and the subsequent pregnancy rate of these animals was 60.0%. The response rate in the second injection was 57.1% and the pregnancy rate was 50.0%. In the second trial, the response rate in the first injection on the rump was 48.7% and the subsequent pregnancy rate was 70.6%. The second injection was given on the shoulder and the response rate was 60.0% and the subsequent pregnancy rate was 25.0%. The data suggests that the site of PGF2 $\alpha$ administration was critical to achieve success in estrous synchronization and pregnancy rates.

• Asian-Australasian Journal of Animal Sciences
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• v.16 no.9
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• pp.1268-1273
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• 2003

Sixty postpartum lactating Friesian cows in 3 treatments at a commercial dairy farm were used to study the effect of using progesterone supplementation with GnRH and PGF2$\alpha$ synchronization with and without timed AI on fertility during summer. Cows in treatment1($Tr_1$) and treatment2 ($Tr_1$) were fitted with progesterone releasing intravaginal device (PRID) device and injected with 10 g GnRH agonist on $51{\pm}3$ d postpartum (pp). Seven days later, PRID was removed and cows received 25 mg PGF2$\alpha$. Two days later, $Tr_1$ cows received another injection of 10 g GnRH and timed AI 16-20 h later. Control cows received only 25 mg PGF2$\alpha$ $58{\pm}3d\;pp$. $Tr_2$ and control cows were AI at detected estrus. Serum progesterone for all cows was determined on days of injection, AI and 21, 23 and 28 d postinsemination. Pregnancy rates from first AI based on serum P4 concentrations on d 21, 23 and 28 postinsemination (50, 40 and 35%) and that based on rectal palpation 40-45 d postinsemination (30, 15 and 15% for $Tr_1$, $Tr_2$ and control cows, respectively) did not differ among the three groups. Whereas, pregnancy rate at 120 d pp for $Tr_1$ (65%) was higher (p<0.05) than that in $Tr_2$ (30%) or control (30%). The overall pregnancy rate was not significantly different (90, 90 and 75% for $Tr_1$, $Tr_2$ and control, respectively). Days open for cows in $Tr_1$ ($100.3{\pm}9$) was less (p<0.03) than that in $Tr_2$ ($130.9{\pm}9$) or control ($135.1{\pm}10$). Results indicate that using PRID device with Ovsynch program had significantly increased pregnancy rate and decreased days open compared to AI at detected estrus after synchronization with GnRH, PRID and PGF2$\alpha$ or synchronization with one injection of PGF2$\alpha$.

• Korean Journal of Animal Reproduction
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• v.27 no.3
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• pp.207-213
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• 2003

This objective of this experiment were to evaluate the effect of various estrus synchronization programs on estrus detection rate and pregnancy rate in Hanwoo. After Postpartum 60 Days, a total of 150 cows divided into 2 groups. Cows Group 1 were treated with one luteolytic dosage of PGF$_2$$\alpha$(25 mg, im; lutalyse. USA) on Day 0, and with a second dosage 14 d later; cows in Group 2 were treated with GnRH(l00 $\mu\textrm{g}$, im; Conceral. Korea) on Day 0, PGF$_2$$\alpha$ 7 d later, GnRH 2 d later, and then time-inseminated approximately 16 h after this second treatment with GnRH. Ovarian morphology was monitored cows by trans-rectal ultrasonography from 24 hr to 32 hrs after second GnRH injection. The result obtained summarized as follows: 1. Cows synchronization of estrus with GnRH+PGF$_2$$\alpha$+GnRH(Ov-synch) and PGF$_2$$\alpha$ were 91.3 and 40.0%, respectively. 2. Induced ovulation were 24 to 32hr after the second GnRH injection, but high induced ovulation was 28hr. 3. High conception rate were 24hr insemination after the second GnRH injection. 4. Conception rate with PGF$_2$$\alpha$, CIDR and GnRH treatment were 50.0, 36.0 and 76.9%, respectively.

• Journal of Embryo Transfer
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• v.20 no.1
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• pp.49-53
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• 2005

This study was conducted to investigate the effects of repetition usage of various estrus synchronization and seasonal breeding in Hanwoo. Body weight(kg) at birth and weaning in calves produced by seasonal breeding are 24.0kg, 75.6kg in female, 24.9kg, 78.3kg in male, respectively. Changes of birth weight(kg) by parity in Hanwoo increased gradually. Raising rates of calves by raising experience of farmer higher than in more 10 years as $88.4\%$ and in more 6 years as $84.0\%$. Delivering rates by induced estrus methods in $PGF_{2}{\alpha}$, PRID, CIDR and $GnRH-PGF_{2}{\alpha}-GnRH$ were $87.0\%$, $87.3\%$, $91.6\%$ and $96.0\%$, respectively. Conception days of post-partum following to induced estrus methods in Control, $PGF_{2}{\alpha}$ PRID, CIDR and $GnRH-PGF_{2}{\alpha}-GnRH$ were 137.1, 147.6, 141.3, 116.6 and 118.0 days, respectively. The results show that repetition usage of various estrus synchronization were not effective on postpartum reproduction in Hanwoo.

• Reproductive and Developmental Biology
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• v.41 no.2
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• pp.25-31
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• 2017

Effective estrus detection and artificial insemination (AI) are necessary for profitable management of dairy herd. In current study, 45 crossbred lactating cows have been selected with the complaint of unobserved oestrus for more than sixty days postpartum. All cows had functional corpus luteum as examined by transrectal ultrasonography. Cows were treated with $PGF_2{\alpha}$ analogue and AI was performed with observed oestrus and then single dose of GnRH was administered. Similar synchronization protocol has been repeated after 14 days in cows that did not repose to first treatment. Remaining cows received additional $PGF_2{\alpha}$ after 14 days of second treatment and timed AI was performed following GnRH administration. Among 45 cows, 28.89% showed estrus after first treatment and 78.79% responded to second hormonal intervention. A higher conception rate (88.89% vs 26.66 and 72.72%) was observed in cows after triple administration of $PGF_2{\alpha}$ and timed AI. We noticed a significant differences in body condition score (BCS, 1~5 scale), postpartum period, and daily milk production between cows that either responded of non-responded following first and second hormonal treatment. In addition, there was a significant positive correlation between daily milk production and BCS, age and postpartum days, milk production and estrus/BCS, and milk production/BCS/estrus and conception rate. Depending upon the findings we conclude that hormonal intervention with $PGF_2{\alpha}$ and GnRH enhances postpartum ovarian cyclicity and help decreasing the days open of dairy herd. Therefore, this finding might provide an excellent guideline for target breeding system for profitable dairy herd management.

• Journal of Embryo Transfer
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• v.23 no.2
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• pp.109-114
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• 2008

This study examined pregnancy and fetal loss rates according to different estrus synchronization protocols and injection of gonadotropin releasing hormone (GnRH) after transfer of Korean Native Cattle embryos to Holstein recipients. In Experiment 1, recipients received no treatment (Control, n = 119); two injections of prostaglandin$F_{2{\alpha}}$ ($PGF_{2{\alpha}}$ ) 11 days apart (PGF group, n = 120); GnRH (day 0)-$PGF_{2{\alpha}}$ (day 7)-GnRH (day 9) (Ovsynch group, n = 120); and CIDR (day 0)-$PGF_{2{\alpha}}$ and CIDR removal (day 7)-GnRH (day 9) (CIDR group, n = 110). In Experiment 2, the control group was received no treatment of GnRH. The treatment groups were received GnRH at embryo transfer (ET) (day 0), 7 days later, 14 days later, ET and 7 days later, 7 and 14 days later, or ET, 7 and 14 days later. Recipients were assigned to treatment randomly and received two in vitro produced blastocysts. Pregnancy was diagnosed at day 60 by palpation per rectum. Fetal loss to term was determined by palpation every 90 days thereafter. In Experiment 1, the pregnancy rate in the CIDR group (59.1%) were higher than in the Control group (42.0%) (p<0.01); fetal loss rates were similar for all groups (12.0 to 18.5%). In Experiment 2, the pregnancy rate in Day 0+7+14 group was higher (60.2%) than the control (40.2%) (p<0.01) and resulted in a lower fetal loss (p<0.05) than the control (4.6 vs. 11.4%). There were no significant difference between other treatment and the control (p>0.05). These results show that pregnancy rates of bovine embryos can be enhanced by CIDR insertion or GnRH $3{\times}$ treatment. Additionally, fetal loss may be reduced with GnRH treatment after ET.