• Journal of Embryo Transfer
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• v.26 no.2
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• pp.91-96
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• 2011

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, ${\leq}$ 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 ${\mu}g$ gonadorelin (Day 0), an injection of $PGF_2{\alpha}$ and removal of the device on Day 7, an injection of 250 ${\mu}g$ 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 ($P{\leq}0.05$) between herds A and B (26.8 vs 50.0%; $2.1{\pm}1.35$ vs $1.37{\pm}0.54$ times, $237.3{\pm}97.8$ vs $164.7{\pm}69.3$ 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 ($63.6{\pm}57.4$ vs $26.1{\pm}24.9$). 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.

• Proceedings of the Korean Society of Embryo Transfer Conference
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• 2002.11a
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• pp.91-91
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• 2002

Considerable attention has been focused on the cryopreservation of semen and estrus induction in dog, as consequence of poor productivity caused by long anestrus period, in order to enhance the productivity of youngs and to preserve the breeds. The objectives of this study were to develop a treatment protocol for estrus induction. Fifty infertilie dogs (age 2∼3 years) were selected for the study and divided into three different estrus induction treatment groups. Group 1: dogs (n=15) were given clomifane (0.1 mg/kg) orally for five days at 12 hr intervals. Group 2: dogs (n=15) were given bromocriptine (50 $\mu\textrm{g}$/kg) orally for five days at 12 hr intervals, followed by single injection intravenously of 500 IU GnRH (Group 3, n=20) when pro-estrus occurred. After being treated, the dogs were evaluated for the rates of estrus induction and time interval lapses from treatment to beginning of the pro-estrus. The estrus induction rates were significantly (P<0.05) higher in both group 2 (9/15, 73.3%) and group 3 (16/20, 80.0%) than that of group 1 (9/15, 60.0%), but did not differ in the groups 2 and 3. No differences were observed in the time interval lapses from treatment to beginning of the pro-estrus in group 2 (7.7 ${\pm}$ 1.2 days) and group 3 (6.9 ${\pm}$ 2.0 days), but significantly (P<0.05) shorter than that of group 1 (9.5 ${\pm}$ 2.1 days). In conclusion, the estrus induction rate of dogs treated with a combination of GnRH and bromocriptine was more effective than use of clomifene or bromocriptine only.

• Korean Journal of Animal Reproduction
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• v.18 no.2
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• pp.127-131
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• 1994

In order to examine the effects of PGF2$\alpha$ on intervals from weaning to estrus and serum progesterone levels seventeen crossbred primiparious sows were randomly alloted to two groups. One group was injected intramuscularly on the day of weaning with 10 mg PGF2$\alpha$ (10mg/2ml, Lutylase). The other group was treated with saline as a control. Serum progesterone concentrations were determined at 24 hour intervals for 12 days after weaning. A serum progesterone level in PGF2$\alpha$-treated group was reached to the lowest level(1.19$\pm$0.38 ng/ml) on day 3 after weaning and remained low(1.26~1.43ng/ml) thereafter. Whereas, the control group showed the lowest level of progesterone on day 4 after wearing, then showed a rapid increase up to 5.02$\pm$0.38ng/ml on day 8 and a rapid decrease was followed. The PGF2$\alpha$ treated group showed an interval from weaning to estrus(5.2$\pm$0.8 days) approximately 2 days shorter than the control(7.4$\pm$3.0 days)(p<0.05).

• Asian-Australasian Journal of Animal Sciences
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• v.16 no.8
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• pp.1093-1101
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• 2003

Reproductive data, such as numbers of days to the first estrus and A.I. service postpartum, number of days to conception, number of A.I. services required for conception, interval between the first estrus and first A.I. service and the average interval of A.I. service in Thai native-Friesian crossbred and pure Friesian dairy cows, were compiled in the National Dairy Training and Applied Research Institute in Chiang Mai, Thailand. The data were analyzed statistically and the effect of milk production on these reproductive traits was investigated. The reproductive efficiency of purebred cows was obviously inferior when compared with crossbred animals, in spite of special care being given to the purebred only in order to alleviate the effect of a tropical climate and provide better feeding. However, the regression analysis between reproductive and lactational parameters revealed a definite antagonistic effect of lactation on reproduction, especially in the purebred cows, which had a larger amount of milk production and longer lactation period. If these effects of lactation were eliminated, there would be no evident difference in reproductive efficiency between purebred and crossbred cows in the conditions of this study. Among the reproductive parameters examined, the number of days to the first estrus and interval between the first estrus and first A.I. service were less affected by breed difference and the magnitude of lactation than other reasons.

• Journal of Embryo Transfer
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• v.27 no.2
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• pp.87-92
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• 2012

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.

• Korean Journal of Agricultural Science
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• v.44 no.4
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• pp.519-524
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• 2017

The present study investigated the impacts of mating age of gilts (A1, < 230 days; A2, 230 - 249 days and A3, $250{\leq}days$) on reproductive performance and litter size of sows at farrowing to weaning. A total of 102 crossbred gilts ($Yorkshire{\times}Landrace$; average days old, 90 days) were purchased from a commercial breeding company. After identification of third estrus, the gilts were artificially inseminated using semen of Duroc boars. Pregnant pigs were allotted to one of three groups including A1, A2, and A3. Experimental diets and water were fed ad libitum during each experimental period which included the first, second, and third parities. Backfat thickness (BFT) of sows was higher in A3 at farrowing in the first parity than in others. At weaning time in the second parity, sows in A3 group showed a numerically higher BFT than those in A1. There was no effect of mating age on the total number of piglets born and total weaned piglets. There was a tendency to decrease the wean-to estrus-interval in the first parity as age increased at mating. Results obtained in the present study indicate that the first mating age does not affect the subsequent parites' reproductive performance; however, weaned to estrus interval tended to decrease in A2 at the first parity.

• 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.1 no.1
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• pp.69-75
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• 1986

These studies were carried out to investigate the induction of superovulation, the synchroniration and the effect of the number of embryos transferred, the developmentai stage of embryos and the donor-recipient synchrony on pregnancy rate in cattle. The results obtained in these studies were as follows: 1. The number of oorpus leuteum(CL) and the embryos reoovered were higher in FSH treated animals than in PMSG treated (9.4 vs 8.1 and 6.1 vs 4.5) and showed the same trend in recovery rate (64.9% vs 55.6%). 2. Two shots of cioprostenol at 11 days showed significantly high no. of animals in estrus in order of crossbred, Holstein and Korean native cattle. No significant differencies were noted in the seoond shots groups. And the interval to estrus and response were shorter and better in second shot group than that in first shot group. 3. The pregnancy rate when additional one embryo was transferred after Al at estrus (52.8%) was higher than the group transferred one (32.8%) or two (36.9%) embryos. 4. The pregnancy rate of embryo in morula stage was better than that in blasto cyst stage (39.3% vs 32.5%). 5. The pregnancy rate in the recipients exhibited estrus later than the donor (66.7%) was the higher than those exhibited estrus (40.3%) or exhibited estrus before the donor (37.5%).

• Asian-Australasian Journal of Animal Sciences
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• v.16 no.2
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• pp.185-188
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• 2003

Data on the use of breeding records of dairy cattle farm of Fenghuang-shan in Chengdu areas during a period of six years is systematically analyzed. The results show that Holstein heifers have their 1st estrus at an average age of $513.6{\pm}46.7$ d which is not related to the calving season. Estrus mostly occurs in the months with mild ambient temperature (March, April, May, November and December). There is a very poor rate of estrus detection; only 30.0% successive estrus is observed within 24 d, 29.3% within 25-48 d, 40.6% over 48 d. The average number of insemination per conception is 1.50 for heifers and 1.74 for cows, but conception rate (CR) is lower in the relatively warm months (July, August and September) ranged from 48.1% to 51.9% compared with 58.1% to 68.5% in other months. High temperature is the most important factor affecting fertilization in warm months, but neither did CR decline immediately with the increased air temperature in June, nor did it increase immediately with the declined air temperature in September. Post partum anestrous period is $119.5{\pm}60.5$ d. The average interval from calving to conception is $159.4{\pm}85.6$ d with only 19.8% of the cows conceived within 85 d of calving. Cows with high milk yield have longer acyclic periods and lower conception rates. Improvement of efficient managements must be a precedent condition in Chengdu areas.

• Asian-Australasian Journal of Animal Sciences
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• v.14 no.5
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• pp.697-700
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• 2001

A prolonged farrowing interval is common on small farms in Nepal and may be attributable to the absence of boar contact at the time of weaning. To examine whether synthetic boar pheromone spray might be of value to aid the stimulation and detection of estrus, 30 village farms, each with a single sow, were recruited into a field study. All sows entered the study on final weaning from their first lactation at 56 days post partum. For 13 treatment sows, a boar pheromone spray (SOA, Intervet, Boxmeer, The Netherlands) was applied each day after weaning whilst 17 other sows did not receive any stimulus (negative control). When estrous was detected by the farmer, sows were taken to the nearest boar for service. There was a significantly shorter weaning to re-mating interval for treatment sows (42.9 V 82.2 day, p<0.05), with a significantly higher proportion of treatment sows rebred by day 60 after weaning (p=0.024, Fishers Test). It is concluded that use of boar pheromones can improve reproductive efficiency of sows kept under Nepalese village conditions.