• Journal of Embryo Transfer
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• v.29 no.2
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• pp.157-161
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• 2014

The study aimed to determine the physical characteristics of estrus mucus and conception rates in dairy cattle. Samples of estrus mucus from the cervix were collected from 108 dairy cattle during heat and were examined for color and consistency. Samples were taken from bred animals at starting from day of breeding to the completion of one estrus cycle. The color of the cervical mucus was studied based on its transparency while the consistency was based on the thinness and thickness of the cervical mucus. The dairy cattle were bred and the pregnancy diagnosis was performed at the $60^{th}$ day post breeding. Findings showed that the estrus mucus of the dairy cattle was transparent in 58.3%, turbid in 31.5% and dirty in 10.2%. It was further observed that the mucus consistency of the dairy cattle was thin in 74.1% and thick in 25.9%. In the pregnant group, 67.3% mucus samples were found transparent, turbid in 23.6% and dirty in 9.1%. However, the corresponding figures for the non-pregnant group had 49.1%, 39.6% and 11.3%. The consistency of cervical mucus was found to be thin in 74.1% and thick in 25.9% of dairy cattle. The conception rates of dairy cattle with thin and thick consistency of cervical mucus were 81.8% and 18.2%, respectively. Pregnant was associated with consistency of cervical mucus (p<0.10). Findings indicated that dairy cattle with thin consistency of cervical mucus and had clear discharge were pregnant cows.

• Korean Journal of Veterinary Research
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• v.26 no.1
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• pp.163-174
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• 1986

The 587 Holstein cows which calved from January 1983 to December 1984 at an integrated dairy farm in Chung-nom province were examined for the incidence of reproductive disorders and their conception rate after treatment. The results obtained were as follows; 1. The incidence of reproductive disorders was 47.9% (281 heads) among 587 heads which calved. 1) As number of calvings increased, the incidence of reproductive disorders decreased. 2) The cows which calved in spring and summer showed significantly higher incidence of reproductive disorders than those which calved in autumn and winter (p<0.05). 3) Among reproductive disorders, ovarian, uterine, cervical and vaginal diseases figured 54.3%, 43.7%, 0.9% and 0.6%, respectively. 4) Among individual genital diseases, endometritis (40.3%) occurred most frequently. 2. Among 281 heads with reproductive disorders, 216 heads(76.9%) conceived after treatment. 1) After treatment of reproductive disorders, the conception rate by number of calvings was in range from 69.6% to 87.5%. 2) The cows which calved in summer and winter showed significantly higher conception rate after treatment of reproductive disorders than those which calved in spring and autumn (P<0.05). 3) The conception rates after treatment of the cows with ovarian, uterine, cervical and vaginal diseases were 66.5%, 81.2%, 33.3% and 50.0% respectively. 4) The cows with endometritis showed the highest conception rate after treatment (85.9%).

• Journal of Embryo Transfer
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• v.21 no.3
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• pp.177-182
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• 2006

This study was conducted to investigate the effects of melengesterol acetate (MGA) and $PGF_{2{\alpha}}$ administrations on serum progesterone level, synchrony of estrus and conception rates in Han-woo. Firstly, ten heifers and one freematin were fed 0.5 mg MGA/day for 14 days in a grain carrier, and after 19 days of MGA feeding, a single injection of 25 mg $PGF_{2{\alpha}}$ were treated. Blood samples were collected to evaluate serum progesterone concentrations from the start of feeding of MGA until the end of feeding and subsequent estrous detection and artificial insemination (AI) at 3 days intervals, and on days of $PGF_{2{\alpha}}$ injection, estrous detection, AI, and 15th and 60th days after AI. The level of progesterone in the blood began to increase from 7 days after MGA feeding, and 9 days after feeding it became 5.4 ng/ml and maintained that level thereafter. On the 33th day when the $PGF_{2{\alpha}}$ was injected, it reached the peak level of 7.6 ng/ml. However, 2-3 days after $PGF_{2{\alpha}}$ injection, it dropped to 1.4 ng/ml drastically (p<0.05). Secondly, one hundred and ninety four Hanwoo heifers or cows were divided into two groups to compare estrous induction and conception rates: the one treated with MGA and $PGF_{2{\alpha}}$, (n=104) and the other with $PGF_{2{\alpha}}$ treatment (two injections at 11 days interval, n=90). The heifers or cows treated with MGA and $PGF_{2{\alpha}}$ were identical to those used as above. The percentages of heifers or cows showed estrus were higher in the $MGA+PGF_{2{\alpha}}$ treatment (91.3%) than in the $PGF_{2{\alpha}}$ treatment (72.2%, p<0.05). Conception rates were also higher in the $MGA+PGF_{2{\alpha}}$ treatment (94.2%) than in the $PGF_{2{\alpha}}$ treatment (88.9%, p<0.05). The results of this experiment indicate that estrus synchronization using $MGA+PGF_{2{\alpha}}$ is more effective than that using $PGF_{2{\alpha}}$ (two injections) in Hanwoo.

• Proceedings of the Korean Society of Embryo Transfer Conference
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• 2003.10a
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• pp.134-134
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• 2003

• 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.

• Journal of Veterinary Clinics
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• v.3 no.1
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• pp.227-233
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• 1986

A total of 600 Holstein cows in Chonnam province was examined to make a diagnosis on the ovarian follicular cyst. By clinical signs and rectal examination, 57 cows were found to have ovarian follicular cyst. Attempts were made to treat the cows which had ovarian follicular cyst with GnRH, HCG respectively. The results obtained were summarized as follows : 1. The rates of estreous induction with GnRH or HCG were 91.4%, 77.2%, respectively. The GnRH treated group was showed significantly higher than HCG treated group. The mean days from the GnRH or HCG treated to estrum were 25.1 and 23.5 days, respectively. 2. The Conception rates with GnRH or HCG treatment were 78.2% and 76.5％, respectively. 3. Services per conception with GnRH or HCG treatment were 1.5 and 2.1 respectively. 4, Days from GnRH or HCG treatment to concept were 38.2 and 45.8 days, respectively. 5. Intramuscular injection with GnRH and intraovarian injection with HCG were revealed the most effective routes in all the other routes.

• Asian-Australasian Journal of Animal Sciences
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• v.13 no.1
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• pp.6-9
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• 2000

The purpose of this study was to evaluate the effect of lower numbers of sperm $(3{\times}10^9)$ per dose liquid semen and type of semen used in artificial insemination (AI) on sow reproductive performance in subtropical area. Semen was supplied by two commercial AI centers. A total of 671 female pigs from seven farms were inseminated with either $3{\times}10^9$ or $5{\times}10^9$ sperm per dose. Two types of semen were used: heterospermic semen from two boars of the same breed and homospermic semen from a single boar. After insemination, conception rate, farrowing rate, total litter size, and number of dead piglets were recorded. The analysis of variance indicated that there was no significant effect of interactions between pig farm, type of semen, or number of sperm on any of the traits measured. There were significant differences in conception rate, farrowing rate, and total litter size among pig farms (p<0.05). The effect of number of sperm per dose liquid semen ($3{\times}10^9$ or $5{\times}10^9$) was not significant. Sows inseminated with homospermic semen showed significantly higher conception and farrowing rates but significantly lower total litter size (p<0.05). In conclusion, the number of sperm per dose liquid semen for AI could be lowered to $3{\times}10^9 $ without affecting reproductive performance in subtropical areas like Taiwan.

• Korean Journal of Animal Reproduction
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• v.13 no.1
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• pp.1-6
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• 1989

A field survey was conducted to obtain the data on reproductive performation of Korean native cattle. The data for this study were taken from 6,461 breeding records of cows raising at general farms in 8 Hanwoo(native cattle) pure breeding areas from June, 1984 through November, 1985. The recycling rate within 30 days, 31 to 60 days, and 61 to 90 days postpartum was 7.5%, 40.0%, and 32.8%, and it amounted to 80.3%, while the non-recyling rate up to 120days postcalving was 8.4%. Conception rate according to insemination(AI) frequencies was 65.7% at 1st AI, 21.3% at 2nd AI, and 8.4% at 3rd AI, respectively. It amounted to 95.4% up to 3rd AI. Clving rate during the spring time was the highest, 39.6%, and tended to be reduced according to summer(31.6%), autumn (16.3%), and winter (12.5%). Spring and summer were the highest seasons for pregnancy and their gestation rates are 33.7% in spring and 39.2% in winter, respectively. The days from calving to estrus and conception, and calving interval of the cows, which calved two or three times, tended to be reduced. However, the more parities, the more they are extended. According to parities, gestation length and services per conception showed irregular tendencies.

• Journal of Embryo Transfer
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• v.14 no.3
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• pp.171-176
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• 1999

This study was carried out to investigate the effect of co-culture system(bovine oviduct epithelial cells; BOEC) and defined culture system (modified TALP ; mTALP) on the conception of embryos transferred, and pregnancy and twin birth rates after transfer of fresh or frozen-thawed bovine blastocysts produced in vitro were also evaluated. Oocytes from the slaughterhouse ovaries were matured and fertilized using general protocol. The results obtained were as the following. The pregnancy rate after transfer was higher in co-culture group than in mTALP group, but was not signficantly different, and there is no difference between fresh embryo group and frozen-thawed embryo group in conception rate. The conception rate was not different whether 3∼4 blastocysts or 2 blatocysts transferred into a recipient, but the production rate of twin calves was significantly higher (p<0.05) when 3∼4 embryos transferred. The average birth weight of twin calves(24.38kg) was numerically, but not significantly lighter than that of single calves(26.68kg).

• Reproductive and Developmental Biology
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• v.30 no.3
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• pp.225-228
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• 2006

This study was undertaken to investigate the effect of ovulation-synchronization(OVSYNCH) method on conception rate after insemination of dairy cattle. The proportion of conception of normal fertility cows(65%) was higher than that in infertility cows(50%) in dairy cows with OVSYNCH treatment. However, there was no significant difference between experimental groups. In another experiment, when the OVSYNCH method was adapted in multiparous dairy cows, the conception rate of experimental group of $30{\sim}35kg/day$ in milk yield was significantly higher than those in groups of $20{\sim}25kg/day$ in milk yield(p<0.05). In conception rates by OVSYNCH method in experimental groups with different parity, the group of 1st parity was significantly higher than in 3rd parity group(p<0.05). The results suggest that conception rate by OVSYNCH method was affected by various reproductive conditions in dairy cattle, and OVSYNCH method could be used to increase the conception rate for infertility cows with hormone disorder.