• Journal of Animal Reproduction and Biotechnology
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• v.35 no.2
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• pp.171-176
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• 2020

Advancing the estrous cycle of mares is an essential breeding strategy that is routinely conducted by Thoroughbred breeders to improve economic outcomes. For this purpose, Equilume light masks have been developed as an alternative to existing technologies such as artificial lighting or hormonal treatments because they are considered as valid as existing methods with additional animal welfare advantages. For example, with the Equilume light masks, horses can be let out into the pasture, whereas they have to be kept indoors during lighting treatment. Because the function of Equilume light mask on the estrous cycle of mares is influenced by environmental factors such as nutrition condition and temperature, Equilume light mask should be studied in various environments. The objective of the present study was thus to verify the effect of Equilume light masks on the onset of the estrous cycle in Thoroughbred mares in South Korea. Mares were randomly selected and separated into two groups at two Thoroughbred horse breeding farms. The mares in the treatment group were equipped with Equilume light masks from November 18 to February 10 the following year. The body condition, the number and size (> 35 mm) of uterine follicles, and the uterine horn score of the mares were assessed on January 6 and February 10. The body condition scores were not different between the two groups. The treatment with the Equilume light mask had no positive effects on developing follicles and the reproductive tract. In conclusion, the use of Equilume light masks did not influence the seasonal resumption of the estrus cycles in Thoroughbred mares in South Korea.

• 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.

• Asian-Australasian Journal of Animal Sciences
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• v.17 no.4
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• pp.479-484
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• 2004

The study was conducted to assess the effect of milk production, parity, stage of lactation, season and individual milk components themselves on milk urea nitrogen (MUN) concentration and other milk components of 3,219 Holstein dairy cows in Korean dairy farms. The MUN concentrations in Korean dairy cows were estimated to 16.68$\pm$5.87 mg/dl. Milk yield was negatively correlated with fat and protein contents and somatic cell counts (SCC) in milk (p<0.01). The increasing MUN concentration has positive correlation with yield and fat content. By increasing somatic cell, milk yield was reduced and MUN level was increased. Cows in spring and winter produced more milk over 1.43 and 0.93 kg/day, respectively, than cows in summer (p<0.01). Milk urea nitrogen concentrations of milk produced in summer and fall were significantly lower (p<0.01) than those in spring and winter. Both MUN concentration and somatic cell counts were highest in winter. Milk yield was lower (p<0.01) in the first calving than other calving time and was tended to increase until the fifth parity and then decrease. Milk urea nitrogen and SCC were not related to parity of cows in this study. Milk yield and SCC were positively related to lactation period while MUN concentrations and milk fat and protein contents were negatively influenced by stage of lactation. In the present study, the relationship between MUN and reproduction of dairy cows was also investigated. Cow produced milk in high MUN concentrations (greater than 18 mg/dl) had more open days than cows in MUN concentrations less than 18 mg/dl. However, no significant difference between MUN concentration levels and frequency of artificial insemination was found in this study. It is suggested that although MUN values for nutritional management and measures of production or reproduction are used, non-nutritional factors should be considered.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2006.05a
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• pp.964-969
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• 2006

The soundscape is a novel attempt to offer comfortable sound environments at the urban public spaces by adding pleasant sounds and removing unagreeable ones. Most important factors to be considered therein are to determine what kind of sounds to offer and how to adjust them to the changing circumstances. But nowadays, the audio system provided in the almost every urban public spaces is just only a PA system with CD player or radio broadcasting music, the provided sound is only intended by the operator. Furthermore, providing the soundscape which fits to the situation and the atmospheric conditions needs enormous effort and time, it is almost impossible with the existing PA systems which installed in the public spaces nowadays. Thus, the new sounds cape reproduction system was developed on the basis of the prior VAFSS(Virtual Acoustic Field Simulation System) systems, which has the artificial intelligence to read out the mood of the field and select the appropriate soundscape to reproduce. In this new system, various environmental sensors with standard voltage, current or resistance output are available simultaneously, and the monitoring with video and sound became available via the TCP/IP communication protocol. The update and control of this system can be very convenient, so the money, time and the effort of maintaining and providing soundscape on the public spaces can be enormously saved. This new soundscape reproducing system was named as Virtual Acoustic Field Simulation System II (V AFSS II).

• Korean Journal of Animal Reproduction
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• v.4 no.1
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• pp.28-34
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• 1980

This experiment was carried out to study effects fo dosage and insemination interval on fertility and hatchability of whole semen and diluted semen with yolk skim milk and skim milk dilutors. The results obtained are as follows: 1. Whole semen showed higher fertility than diluted semen with yolk skim milk and skim milk dilutors. In case of diluted semen, the fertility was higher in 0.04$m\ell$ dosage than 0.02$m\ell$ and in skim milk than yolk skim milk dilutor. 2. The average fertility in inseminational intervals of 6, 5, 4 and 3 days was 52.4, 35.5, 48.7 and 44.2% in whole semen and 40.6, 17.2, 13.9 and 20.5% in 0.04$m\ell$ diluted semen with yolk skim milk dilutor. The fertility was not improved by shortening of insemination interval. 3. There was no considerable difference in hatchability of fertilized egg among the dosage of 0.02$m\ell$ of whole semen, 0.02$m\ell$ and 0.04$m\ell$ of diluted semen with yolk skim milk, and among the insemination intervals of 6, 5, 4 and 3 days. 4. Some differences in fertility among the passed days after insemination were decreased in the whole semen by shortening insemination interval from 6 and 5 days to 4 and 3days and also decreased in the diluted semen by shortening it to 3 days and by increasing dosage from 0.02$m\ell$ to 0.04$m\ell$. 5. Hatchability of fertilized egg showed no difference among the passed days during 6 days insemination interval both in the whole semen and the diluted semen. 6. The whole semen and the diluted semen with skim milk had not considerable difference in fertility among the passed days during 3 and 4 days insemination intervals, but the diluted semen with yolk skim milk had. 7. Hatchability of fertilized egg from the whole semen diluted semen with yolk skim milk and skim milk dilutors showed no difference among the passed days during 3 and 4 days insemination intervals.

• Korean Journal of Animal Reproduction
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• v.3 no.2
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• pp.57-63
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• 1979

In this study, pooled whole semen and diluted semen with skim milk lactose solution and yolk skim milk lactose solution were inseminated at 6 and 7 days interval during 90 days. Egg production, fertility and hatchability were investigated. The results obtained from this study are summarized as following: 1. The average fertility of 57.8% for whole semen was clearly higher than that of 35.2% for diluted semen during 90 days insemination trial. 2. The highest fertility was a, pp.ared from 35 to 99 days after insemination for the whole semen, but from 28 to 60 days for the diluted semen during 90 days insemination trial. 3. In case of 7 days insemination interval, highest fertility of 86.6 and 70.0% for the whole semen and the diluted semen was a, pp.ared on 2 days after insemination and thereafter the fertility was gradually decreased according to passage of insemination. The lowest fertility of 35.0 and 0.0% for the whole semen and diluted semen was a, pp.ared on 1 day after insemination. 4. In case of 6 days insemination interval, highest fertility of 80.0 and 55.8% for the whole semen and the diluted semen was also a, pp.ared on 2 days after insemination and thereafter the fertility was slowly decreased according to passage of insemination. However, lowest fertility of 25.0 and 20.0% for the whole semen and the diluted semen was a, pp.ared on 0 day after insemination. 5 It suggests that there was no difference in fertility between the skim milk lactose and the yolk skim milk lactose dilutors. 6. In case of whole semen, average fertility of 7 days insemnaition interval was a, pp.rently lower than that of 6 days, however there was no difference in fertility between 6 and 7 days insemination interval. 7. Insemination interval of 6 and 7 days and passage day after insemination did not alter egg production and hatchability of fertilized egg production and hatchability of fertilized egg in both whole and diluted semen.

• Korean Journal of Animal Reproduction
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• v.9 no.1
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• pp.31-35
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• 1985

This study was carried out with 46 cows to investigate the ovarian response to the administration of PMSG, PGF2$\alpha$ and hCG, and the developmental stage of embryos recovered. Superovulation was induced by the injection of 2,000IU to 3,000IU PMSG on the days of 7-13 of the estrus cycle followed 48 hours later by the injection of 22.5mg PGF2$\alpha$. Of 29 cows treated with 3,000IU PMSG and 22.5mg PGF2$\alpha$ 18 cows were given 2,000IU hCG at the onset and 7 after artificial insemination. The results obtained were summarized as follows; 1. The number of developed follicles per cow after an injection of 2,000, 2,500, 3,000IU of PMSG and 3,000 PMSG-2,000IU hCG in combination with 22.5mg PGF2$\alpha$ were 12.6, 19.6, 21.5 and 29.3, respectively. This result indicated that the no. of developed follicles per cow was increased according to the increase of PMSG dosage and the combination with hCG injection. 2. The highest number of ovulation was 17.1 in cows treated with PMSG-hCG and the number of matured corpus luteum was increase as the dosage of PMSG was higher. 3. Ovulation rate from cows treated with 2,500IU PMSG was 71.0% and this reulst was higher than the average of ovulation rate (59.3%). 4. Average recovery rate was 36.8%(232/631), and the number of ova per cow was 5.0. 5. Of 232 recovered embryos, the number of morulae and blastocysts were 76 (32.8%) and 83 (35.8%), respectively. 6. 28.4% of total recovered embryos was abonormal morphologically.

• Genomics & Informatics
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• v.13 no.4
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• pp.137-145
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• 2015

Selective sweep can cause genetic differentiation across populations, which allows for the identification of possible causative regions/genes underlying important traits. The pig has experienced a long history of allele frequency changes through artificial selection in the domestication process. We obtained an average of 329,482,871 sequence reads for 24 pigs from three pig breeds: Yorkshire (n = 5), Landrace (n = 13), and Duroc (n = 6). An average read depth of 11.7 was obtained using whole-genome resequencing on an Illumina HiSeq2000 platform. In this study, cross-population extended haplotype homozygosity and cross-population composite likelihood ratio tests were implemented to detect genes experiencing positive selection for the genome-wide resequencing data generated from three commercial pig breeds. In our results, 26, 7, and 14 genes from Yorkshire, Landrace, and Duroc, respectively were detected by two kinds of statistical tests. Significant evidence for positive selection was identified on genes ST6GALNAC2 and EPHX1 in Yorkshire, PARK2 in Landrace, and BMP6, SLA-DQA1, and PRKG1 in Duroc. These genes are reportedly relevant to lactation, reproduction, meat quality, and growth traits. To understand how these single nucleotide polymorphisms (SNPs) related positive selection affect protein function, we analyzed the effect of non-synonymous SNPs. Three SNPs (rs324509622, rs80931851, and rs80937718) in the SLA-DQA1 gene were significant in the enrichment tests, indicating strong evidence for positive selection in Duroc. Our analyses identified genes under positive selection for lactation, reproduction, and meat-quality and growth traits in Yorkshire, Landrace, and Duroc, respectively.

• Journal of Animal Reproduction and Biotechnology
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• v.36 no.4
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• pp.230-238
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• 2021

This study attempted to determine the characteristic features of postpartum dairy cows during their return to estrus. Moreover, it investigated the effects of abnormal ovarian cycles (AOC) on subsequent reproductive performance and the relationship between normal ovarian cycles (NOC) and the blood urea nitrogen (BUN) level postpartum. Incidentally, 56.3% of the Holstein cows and 66.7% of the Jersey cows had NOC, whereas the 43.7% and 33.3% of the Holstein and Jersey, respectively, had AOC. Within 100 days of calving, the cows with AOC had significantly lower rates of artificial insemination (AI) submission as well as pregnancy and a significantly longer interval to first AI, as compared to that in the cows with NOC. Additionally, the cows with NOC had a significantly higher first AI conception rate than that in the cows with AOC. In this study, of the 32 Holstein cows, 8 resumed their ovarian cycle within 20 days of calving, 10 resumed the cycle with 21-40 days of calving, 8 within 41-60 days of calving, while the remaining 6 did not resume their ovarian cycles until 60 days postpartum. Furthermore, the likelihood ratios of incidence of NOC are 0.93, 1.94, and 0.38, respectively, in the groups with BUN levels < 15, 15-19.9, and ≥ 20 mg/dl. In conclusion, AOC postpartum adversely affects reproductive performance such as AI submission rate, pregnancy rate, interval to first AI and first AI conception rate; moreover, an increase or decrease in the BUN levels beyond 15-19.9 mg/dL leads to the AOC postpartum.

• Journal of Animal Reproduction and Biotechnology
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• v.36 no.4
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• pp.212-219
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• 2021

The aims of this study were to measure the ultrasonographic biometry of genitalia of the indigenous rams and observe the relationship of biometry on semen parameters. The epididymal volume was significantly reduced (p < 0.01) after semen collection compared with before collection for both left and right part in all rams. The cumulative results showed that although there was no significant difference in length, width and volume of epididymis between before and after semen collection, however the values were lower after collection. The epididymal length was significantly correlated with epididymal volume (p < 0.01), semen motility (p < 0.05) and semen morphology (p < 0.01). Epididymal width was only significantly correlated with epididymal volume (p < 0.01) not with the semen parameters. Epididymal volume had a significant correlation only with semen morphology (p < 0.01).The scrotal circumference had the significant correlation with semen density, mass activity, concentration and motility (p < 0.01). The epididymis had the similar or slightly increased echogenicity as compared to the normal testis. During whole study, some white spots were found on testis which did not affect the semen quantity and quality. Significant variation was observed only for semen concentration and motility among the rams (p < 0.05). The overall normal morphology was 90.5 ± 4.6% with highest percentage of coiled tail abnormalities.