• Journal of Practical Agriculture & Fisheries Research
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• v.25 no.4
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• pp.111-117
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• 2024

Reproductive research such as artificial insemination and embryo transfer is necessary to produce high-quality riding horses. In this study, we investigated the effects of estrus synchronization and ovulation induction methods, which can be considered the basis of artificial insemination in horses, on the hormone concentration and artificial insemination pregnancy rate of mares. For the purpose of synchronization of estrus in horses, Cidr-plus insertion method, Regumate feeding method, and 150mg progesterone + 10mg estradiol mixed administration method were used. In the Cidr-plus insertion method and the Regumate feeding method, the progesterone concentration reached the appropriate level for ovulation induction on the 8th day of administration. The mixed administration method of 150mg progesterone + 10mg estradiol maintained the progesterone concentration at an appropriate level immediately after administration. With the administration of PGF2a and hCG, progesterone concentration decreased rapidly, making ovulation induction possible. As a result of comparing the pregnancy rate between natural estrus and estrus synchronization, the pregnancy rate was found to be higher in estrus synchronization and ovulation induction. From the results of this study, it is insufficient to judge the effect of the pregnancy rate due to the small number of tests, but in terms of usability, estrus synchronization and ovulation induction were useful. Therefore, it is expected to contribute to improving the efficiency of future roadster production.

• Asian-Australasian Journal of Animal Sciences
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• v.22 no.6
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• pp.774-780
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• 2009

The objectives of this study were to test the efficacy of induction of estrus and determine the timing of ovulation in relation to preovulatory LH and estrogen surges in cycling Murrah buffaloes subjected to Heatsynch protocol (GnRH-$PGF_2{\alpha}$-Estradiol benzoate). In experiment 1, the buffaloes (n = 10) were treated with Heatsynch protocol and observed for estrus and ovulation. In experiment 2 and 3, 30 cycling Murrah buffaloes were used to investigate the efficacy of Heatsynch protocol in terms of conception rates in summer (experiment 2) and winter (experiment 3) seasons. Fixed time A.I. was performed in all the buffaloes at 48 and 60 h post-estradiol benzoate (EB) injection. All buffaloes responded to the Heatsynch protocol with expression of estrus for which ovulations were induced in 8 buffaloes (80%). Mean time interval from the EB injection to ovulation was 50.0${\pm}$2.0 h (range 44.0 to 60.0 h). The interval from the end of LH surge to ovulation was 18.5${\pm}$2.47 h (range 8 to 26 h). The interval from end of estrogen surge to ovulation was 26.75 ${\pm}$2.07 h (range 22 to 36 h). Mean LH peak after EB injection occurred at 20.81${\pm}$1.61 h (range 14 to 28 h) and mean estrogen peak after EB injection occurred at 9.62${\pm}$1.03 h (range 7 to 16 h). Hence, the mean estrogen peak preceded the mean LH peak by 11 h. It was observed that the percentage of conceptions to total number of estruses for control buffaloes was 18 and 30 in summer and winter, respectively, whereas it increased to 26 and 40 in Heatsynch treated buffaloes in respective seasons. The results suggest the possibility of using Heatsynch treatment followed by fixed time A.I. in buffaloes for fertility improvement, especially since the incidence of silent heat in buffaloes is very high.

• Journal of Embryo Transfer
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• v.26 no.2
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• pp.105-109
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• 2011

Ovulation synchronization (ovsynch) has proved to increase the number of insemination in cattle by overcoming the problems of heat detection. The aim of this study was to do ovsynch in water buffaloes where heat detection is a major reproductive problem and to determine the conception rates after timed artificial insemination (TAI). Twenty cyclic buffaloes at ${\geq}$ 60 days postpartum were selected by examining 24 unobserved estrus buffaloes based on milk progesterone assay (progesterone concentration ${\geq}$ 1.0 ng/ml) from the Mymensingh district of Bangladesh. Ovsynch treatment regimen was started irrespective of the stage of estrous cycle. Gonadorelin (500 ${\mu}g$) was injected intramuscularly at Day 0 followed by Alfaprostol (8 mg) at Day 7. A second injection of Gonadorelin was given at Day 9 and TAI was done with frozen semen from Mediterranean buffalo bulls at 16~20 hours of the second Gonadorelin injection. Milk progesterone ELISA at Day 10~12 post AI confirmed ovulation in 16 out of 20 (80%) buffaloes (progesterone concentration ${\geq}$ 1.0 ng/ml). High progesterone concentration (${\geq}$ 1.0 ng/ml) at Day 10~12 and Day 22~24 of AI showed pregnancy in six out of 20 (30%) buffaloes. Pregnancy was further confirmed by ultrasonography at Day 40 in these six buffaloes. In conclusion, ovsynch followed by TAI could be applied in cyclic buffaloes for overcoming the estrus detection problems; however, more studies are needed to increase the conception rate.

• Journal of Embryo Transfer
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• v.18 no.3
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• pp.187-193
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• 2003

Recently a protocol was developed that precisely synchronizes the time of ovulation in Hanwoo. Cows were treated with GnRH on Day 0, PGF$_2$$\alpha$ 7 d later, GnRH 2 d later, and then time-inseminated approximately 24 h after this second treatment with GnRH. Ovarian morphology was monitored cows by trans-rectal ultrasonography 6.5MHz linear transrectal probe(Sonovet - 600., Medison co. Korea) from 24 hr to 31 hrs after second GnRH injection. The result obtained summarized as follows - 1. Induced ovulation were 24 to 31hr after the second GnRH injection, but high induced ovulation was 28hr. 2. Conception rate with HML(High meat lin) and HIL(High milk lin) treatment were 48.1％(38/79) and 43.9％(40/91), respectively. 3. Conception rate of 1∼2 parity and 3∼4 parity was 44.3％ and 55％, respectively. 4. Conception rate of spring, autumn was more increased, 47.3％ than summer.

• Asian-Australasian Journal of Animal Sciences
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• v.32 no.8_spc
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• pp.1284-1295
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• 2019

Considerable progress in reproduction of dairy goats has been made, with advances in reproductive technology accelerating dairy goat production since the 1980s. Reproduction in goats is described as seasonal. The onset and length of the breeding season is dependent on various factors such as breed, climate, physiological stage, male effect, breeding system, and photoperiod. The reproductive physiology of goats was investigated extensively, including hypothalamic and pituitary control of the ovary related to estrus behavior and cyclicity etc. Photoperiodic treatments coupled with the male effect allow hormone-free synchronization of ovulation, but the kidding rate is still less than for hormonal treatments. Different protocols have been developed to meet the needs and expectations of producers; dairy industries are subject to growing demands for year round production. Hormonal treatments for synchronization of estrus and ovulation in combination with artificial insemination (AI) or natural mating facilitate out-of-season breeding and the grouping of the kidding period. The AI with fresh or frozen semen has been increasingly adopted in the intensive production system, this is perhaps the most powerful tool that reproductive physiologists and geneticists have provided the dairy goat industry with for improving reproductive efficiency, genetic progress and genetic materials transportation. One of the most exciting developments in the reproduction of dairy animals is embryo transfer (ET), the so-called second generation reproductive biotechnology following AI. Multiple ovulation and ET (MOET) program in dairy goats combining with estrus synchronization (ES) and AI significantly increase annual genetic improvement by decreasing the generation interval. Based on the advances in reproduction technologies that have been utilized through experiments and investigation, this review will focus on the application of these technologies and how they can be used to promote the dairy goat research and industry development in the future.

• Journal of Embryo Transfer
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• v.23 no.2
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• pp.81-86
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• 2008

This study compared the pregnancy rates of Korean native donor cattle after either a timed artificial insemination (TAI) or embryo transfer (TET) following the synchronization of ovulation using a controlled internal drug release (CIDR) device together with estradiol benzoate (EB) and prostaglandin $F_{2{\alpha}}$ ($PGF_{2{\alpha}}$). Fifty five cows and 8 heifers which had been previously used for embryo production were assigned to two treatments: (1) Thirty-two cattle received a CIDR device and 2 mg EB (Day 0), 25 mg $PGF_{2{\alpha}}$ injection at the time of CIDR removal on Day 7, and 1 mg EB injection on Day 8. All of the cattle received a TAI 30 h (Day 9) after the second EB injection (TAI group). (2) Thirty-one cattle received the same hormonal treatments as in the TAI group. The cattle with corpus luteum (CL) received a TET on Day 16 using frozen-thawed embryos (TET group). Ultrasonographic observations demonstrated that the proportion of cattle with synchronized ovulation on Day 10 and the concomitant formation of new CL on Day 13 did not differ between groups (p>0.05); the overall mean rates were 65.1 and 73.0%, respectively. The conception and pregnancy rates did not differ (p>0.05) between the TAI (12.5% and 12.5%) and TET groups (13.0% and 9.7%), respectively. We conclude that the pregnancy rate following TAI or TET in Korean native donor cattle was poor, which might be due in part to a poor synchrony of ovulation and concomitant CL formation.

• Journal of Embryo Transfer
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• v.2 no.1
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• pp.33-35
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• 1987

This study was carried out to investigate the seasonal effect on the recovery rate of embryos in donors and on the conception rate in recipients following embryo transfer. The results obtained from this experiment were summarized as follows: 1. The ovulation point in winter and summer was 28.6 and 28.6, respectively. There was no difference in ovulation point between two seasons. More embryos recovered in the winter (27,0) than the summer (20.9). 2. The number of CL, unruptured follicle, hemorrhagic follicle, young born and pregnancy rate in the winter were 6.0,4.8,1.5,1.8 and 75%, and those in the summer were 2.9,5.7, 3.8, 2.2 and 46.7%, respectively. The rate of synchronization of recipients in the winter showed better results than that in the summer.

• 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.

• Korean Journal of Animal Reproduction
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• v.27 no.3
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• pp.241-248
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• 2003

This study was conducted to determine the effects of progestagen (Synchromate-B, Veramix, CIDR) and hormone (PMSG, FSH, hCG) treatments on superovulation and estrous synchronization in Korean native goats. Goats were initially superovulated by using progestagens (Synchromate-B, Veramix, CIDR) and hormones (FSH, PMSG, hCG). The progestagens were removed after 15 days of insertion and 0.88 mg of FSH was injected intramuscularly twice a day from day 12 to day 15. In addition, 150 IU of PMSG and 200 IU hCG were injected intramuscularly in the morning of day 12 and in the afternoon of day 15, respectively. Estrous synchronization was induced by the progestagen releasing devices for 13 days and intramuscular injection of 400 IU PMSG in the morning of day 11. The results were summarized as follows: 1. The responses of superovulation treated with three types (Synchromate-B, Veramix, CIDR) of progestagen were 98.6, 99.4 and 98.8%, respectively. The average ovulation rates with Synchromate-B, Veramix and CIDR were 12.58 $\pm$ 6.52, 12.91 $\pm$ 7.27 and 11.28 $\pm$ 6.33, respectively. The average ovulation rates of Synchromate-B and Veramix treatments were significantly higher than that of the CIDR treatment (P<0.05). 2. The responses of estrus synchronization treated with Synchromate-B, Veramix and CIDR were 52.9, 72.9 and 75.7%, respectively. Veramix and CIDR treatments on estrous synchronization were significantly higher than the Synchromate-B treatment (P<0.05). Among the estrous synchronized goats, the estrous ovulation rates with Synchromate-B, Veramix and CIDR were 2.11 $\pm$ 1.89, 1.35 $\pm$ 0.87 and 1.43 $\pm$ 0.96, respectively. The estrous ovulation rates of the Synchromate-B treatment were significantly higher than those of the other treatments (P<0.05). 3. The average superovulation rates were 11.76 $\pm$ 6.00 and 11.07 $\pm$ 6.46 for the PMSG treatment and control groups, showing that there was no PMSG effects for the superovulation treated with CIDR.

• Korean Journal of Animal Reproduction
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• v.11 no.3
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• pp.223-229
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• 1987

This study was carried out to investigate effects of superovulation and time of embryo recovery on ovarian response, recovery rate and developmental stage of embryo in donor and effects of methods of synchronization, number of corpus luteum (CL), stage of embryo and time of embryo transfer on ovarian response, conception rate and number of newborn in recipients which were transferred on 2.5, 3.5 and 4.5 days after synchronization. The results obtained are as follows; 1. The ovulation point of superovulated donor on 2.5, 3.5 and 4.5 days after copulation was 23.3, 35.3 and 23.3, respectively. The number of embryos recovered from the donors on 2.5, 3.5 and 4.5 days after copulation was 23.3, 25.8 and 19.8, respectively. The ovulation point and number of embryos recovered on 3.5 days were greater than those of 2.5 and 4.5 days. Among 232 embryos recovered on 3.5 days after copulation, 84 were blastocyst and 62 were hatching blastocyst. 2. The number of CL in recipients on 2.5, 3.5 and 4.5 days after synchronization was 3.2, 2.9 and 3.8 and showed no difference among the days. 3. When the number of CL was 0, 2-3, 4-6 and more than 7 the pregnancy raet of recipients was 0, 37.5, 66.7 and 75%, respectively. The pregnancy rate of recipients increased as the number of CL increased. 4. The pregnancy rate of transferred morula, blastocyst and hatching blastocyst was 32.0, 37.2 and 24.7%, respectively. The blastocyst nhowed highest pregnancy rate. 5. When the recipients were synchronized by HCG, the number of CL, unruptured follicle, hemorrhage, pregnancy rate and number of young were 5.5, 6.4, 3.3, 72.7% and 3.3, whereas that of GnRH were 2.3, 4.4, 2.8, 25.0% and 1.2, respectively. Recipients synchronized by HCG showed better results than GnRH. 6. When the embryos were collected on 2.5 days after copulation and transferred to the synchromized recipients, the pregnancy rate and the number of young born was 62.58% and 3.1, respectively. Those of 3.5 and 4.5 days after copulation was 57.1% and 1.3, and 37.5% and 1.6. The 2.5 days showed higher pregnancy rate and number of young born than 3.5 and 4.5 days.