• 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 The Korean Society of Grassland and Forage Science
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• v.4 no.2
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• pp.152-157
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• 1983

This study was carried out to investigate changes in the quality and botanical composition of native pasture during the grazing period. The results obtained were as follows: 1. On all the farms, the total dry matter yield of native pasture was much higher in the October-cut than in the July-cut. 2. The crude protein content was higher in the July-cut than in the Oct.-cut, while the crude fiber content gave opposite results. There was the same tendency on all the farms. 3. When the six farms were compared, the highest crude protein content was found at Hawon and Haian farm, and cows on these farms showed the highest daily weight gain. Ohra farm had the lowest crude protein and the cows on this farm the lowest daily weight gain. 4. The botanical composition of the main species distributed was 58.1% Zoysia japonica, 16.4 Pteridum aquilinum, and 3.8% Miscanthus sinensis. In the case of family, 72.1% were Gramineae, 1.8% Leguminosae, and 16.4% Pteridacea. 5. According to botanical composition of a family, Hawon farm had the highest daily weight gain and the highest rate of Gramineae and Leguminosae. Ohra and Youngkang farms had the lowest weight gains, but the native grassland on these farms contained a high proportion of Pteridum which is toxic to cattle.

• Korean Journal of Animal Reproduction
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• v.8 no.2
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• pp.79-86
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• 1984

This cepseiment was carried out to cerify the effect of thawing methods and preservative temperature on the sperm motility and fertility after thawing semen with plastic straws in fresh and warm water. Sperm motility in vitro stored at room temperature after thawing were conducted by the various storage hours. A field trial after thawing semen with warmed water in straws from Cheju native cows involving 4 technicians and 800 cows first (or second) services gave the following results. The thawing methods of warmed water for one minute in semen motility were considerably higher than that in iced water during 12 hours after thawing semen, however, the sperm survival index of ice-water shwed a better results according as the time passed away, but not significant differences. Preservative temperaure at 5$^{\circ}C$ (iced water) after thawing gave significantly better results than that of thawed at 3$0^{\circ}C$ (warmed water). The N R rate to 175 inseminations with semen thawed at 15-2$0^{\circ}C$ (fresh water) was 82.8%, 80.9% for 610 inseminations thawed in warm water. Conception rate ofthe semen thawed in warm water for 10-60 secs gave no significant difference among storage hours, because the semen used to be inseminated within one hour almost, but in decreased when semen thawed at the period of one minute over.

• Korean Journal of Veterinary Research
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• v.43 no.2
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• pp.283-288
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• 2003

This survey was carried out to investigate the seroprevalence of antibodies to Neospora caninum in Korean native cattle (KNC) raised in Kangwon province in Korea. A total of 867 sera collected from KNC were tested for N. caninum antibodies using an indirect immunofluorescent antibody test (IFAT). One hundred and fifty five (17.9%) KNC were positive by IFAT. Seroprevalence of cows was 19.6% (44/224) and seroprevalence of boars was 17.3% (111/643). Among the seroprevalences of cattle according to the raised areas, five counties or cities, Hwacheon was 33.3% (1/3), Wonju was 30.8% (4/13), Chuncheon was 25.8% (24/93), Hongcheon 18.3% (22/120) and Wheongsung was 16.6%(104/628). It was proved that KNC raised in Kangwon provinces exposed extensively and seriously to N. caninum.

• Korean Journal of Veterinary Research
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• v.28 no.2
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• pp.261-270
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• 1988

This study was performed to investigate the effect of gestation on the histological and histochemical changes of the uterine cervix of the native Korean cattle. A total of 110 cows obtained from the Chonhuk abattoir were divided into six groups. The 1st group was of 9 non-pregnant cows and 101 singleton pregnant cows were grouped into 5 groups from pregnant I to pregnant V according to gestation periods by means of crown rump length measures. For light microscopy the tissues were fixed in 10% neutral formalin and processed routinely for paraffin sections The $6{\mu}m$ sections were taken and stained with H-E, Alcian blue pH 1.0, Alcian blue pH 2.5, Alcian blue pH 2.5/PAS, PAS reaction, toluidin blue, and trichrome. The results obtained were as follows: 1. The cervical lengths and widths were increased in relation to advancing gestation. 2. The cervical folds of the pregnant groups were increased and complicated with many branches, and the cervical muscosal epithelia were increased in according to advancing gestation. 3. As advancing gestation, the tunics muscularis of cervix was increased following moderate distribution of fibroblast and vascularity, meanwhile decreased mast cells were found. 4. The cervical mucosubstance was composed of mixed mucopolysaccharides; the acid mucus was increased from the early pregnant state but the neutral mucus was found after pregnant IV, and the mucus was stained deeply in each staining in the fold cavity in according to gestation state.

• Korean Journal of Veterinary Research
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• v.22 no.2
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• pp.91-98
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• 1982

This study was conducted to determine the interrelationship between the weight of various visceral organs and the live weight of Korean native cattle with particular regard to female ones. One hundred and eighty-five of 2 to 6 years and one hundred and fifty-six Korean native cow of over 7 years of age were examined at the Busan slaughter house during the lest quarter of 1979. The results obtained are summarized as follows: 1. The average live weight of 72 years old cows examined was 297.09kg, while these weight of visceral organs such as liver, lung, heart, left kidney, right kidney and spleen being 4301.09, 2165.22, 1355.43, 346.74, 350 and 991.30g, respectively. The length, width and thickness of the spleen were 49.0, 12.92 and 2.95cm, respectively. 2. The average live weight of 3 years old cows examined was 306.56kg, while these weight of visceral organs such as liver, lung, heart, left kidney, right kidney and spleen being 4099.07, 2144.44, 1383.33, 326.85, 325.93 and 964.82g, respectively. The length, width and thickness of the spleen were 43.3, 12.37 and 2.80cm, respectively. 3. The average live weight of 4 years old cows examined was 314.67kg, while these weight of visceral organs such as liver, lung, heart, left kidney, right kidney and spleen being 4186.67, 2292.50, 1392.50, 346.67, 343.33 and 932.50g, respectively. The length, width and thickness of the spleen were 47.01, 12.55 and 3.08cm, respectively. 4. The average live weight of 5 years old cows examined was 328.90kg, while these weight of visceral organs such as liver, lung, hearts left kidney, right kidney and spleen being 4465.32, 2394.35, 1493.55, 370.16, 335.97 and 997.58g, respectively, The length, width and thickness of the spleen were 49.17, 12.76 and 3.16cm, respectively. 5. The average live weight of 6 years old cows examined was 334.97kg, while these weight of visceral organs such as liver, lung, heart, left kidney, right kidney and spleen being 4585.29, 2552.79, 1555.89, 364.70, 373.24 and 985.29g, respectively. The length, width and thickness of the spleen were 48.27, 12.66 and 2.78cm, respectively. 6. The average live weight of 156 cows (over 7 years of age) examined was 344.91kg, while these weight of visceral organs such as liver, lung, heart, left kidney, right kidney and spleen being 4730.77, 2651.44, 1554.39, 407.37, 409.42 and 1101.06g, respectively. The length, width and thickness of the spleen were 51.04, 13.21 and 3.08cm, respectively. 7. Total average live weight of 341 cows (from 2 to 6 and over 7 years of age) examined was 332.44kg, while these weight of visceral organs being 4550.95, 2497.13, 1500.76, 380.18, 382.27 and 1047.98g, respectively. The length, width and thickness of the spleen were 52.01, 12.96 and 3.02cm, respectively. 8. The correlation coefficients between the live weight of 341 cows and their visceral organs were found to be highly significant (P<0.01), except fort for the length of spleen

• Asian-Australasian Journal of Animal Sciences
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• v.27 no.9
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• pp.1250-1253
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• 2014

The objective of this study was to estimate the parameters of Gompertz growth curves with the measurements of body conformation, real-time ultrasound longissimus dorsi muscle area (LMA) and backfat thickness (BFT) in Hanwoo cows. The Hanwoo cows (n = 3,373) were born in 97 Hanwoo commercial farms in the 17 cities or counties of Gyeongbuk province, Korea, between 2000 and 2007. A total of 5,504 ultrasound measurements were collected for the cows at the age of 13 to 165 months in 2007 and 2008. Wither height (HW), rump height (HR), the horizontal distance between the top of the hips (WH), and girth of chest (GC) were also measured. Analysis of variance was conducted to investigate variables affecting LMA and BFT. The effect of farm nested in location was included in the statistical model, as well as the effects of HW, HR, WH, and GC as covariates. All of the effects were significant in the analysis of variance for LMA and BFT (p<0.01), except for the HR effect for LMA. The two ultrasound measures and the four body conformation traits were fitted to a Gompertz growth curve function to estimate parameters. Upper asymptotic weights were estimated as $54.0cm^2$, 7.67 mm, 125.6 cm, 126.4 cm, 29.3 cm, and 184.1 cm, for LMA, BFT, HW, HR, WH, and GC, respectively. Results of ultrasound measurements showed that Hanwoo cows had smaller LMA and greater BFT than other western cattle breeds, suggesting that care must be taken to select for thick BFT rather than an increase of only beef yield. More ultrasound records per cow are needed to get accurate estimates of growth curve, which, thus, helps producers select animals with high accuracy.

• Korean Journal of Veterinary Research
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• v.44 no.2
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• pp.287-292
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• 2004

The objective of present study was to ascertain genetic diversity for cattle parentage testing. A total of 59 random cattle samples(29 Korean native cattle and 30 dairy cows) were genotyped by using 11 microsatellite loci(BM1824, BM2113, ETH10, ETH225, EH3, INRA23, SPS115, TGLA122, TGLA227, TGLA53, and TGLA126). This method consisted of multiplexing PCR procedure and showed reasonable amplification of all PCR products. Genotyping was performed with an ABI 310 genetic analyzer. The number of alleles per locus varied from 5 to 11 with a mean value of 6.73 in the Korean native cattle(KNC), 4 to 9 with a mean of 5.91 in dairy cows(DC). Expected heterozygosity was ranged 0.534~0.855(mean 0.732), 0.370~0.866(mean 0.692) in the KNC and DC, respectively. PIC value was ranged 0.485~0.821(mean 0.684), 0.336~0.834(mean 0.640) in the KNC and DC, respectively. Of the 11 markers, 7 markers(ETH10, EH3, INRA23, SPS115, TGLA122, TGLA227, TGLA53) and 3 markers(INRA23, TGLA227, TGLA53) have relatively high PIC value (>0.7) in the KNC and DC, respectively. The total exclusion probability of 11 microsatellite loci was 0.9997 and 0.9991 in the KNC and DC, respectively. These results present basic information for developing a system for parentage verification and individual identification in the KNC and DC.

• Korean Journal of Veterinary Research
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• v.30 no.2
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• pp.171-175
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• 1990

Radioimmunoassay for progesterone in Korean native cows was developed using the anti-4-pregnen-$11{\alpha}$-ol-3,20-dione-hemisuccinate bovine serum albumin as an antibody. The final dilution of antibody was 1 : 5,000. The percentage recoveries of [$^3H$] progesterone was $83.5{\pm}1.6$. The sensitivity of the assay was 8 pg per ml. The intra- and interassay coefficients of variation for the quality controls were 6.2 and 10.4%, respectively. This radioimmunoassay can be applied to puberty, estrus dectection, pregnancy diagnosis, postpartum period and diagnosis of reproductive disorders in domestic animals.

• Journal of Embryo Transfer
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• v.33 no.4
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• pp.265-270
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• 2018

Up-to-date artificial insemination (AI) using frozen sperm consider as the most widely using technology for improvement of Korean Native Cow (Hanwoo) embryo production. However, it is time consuming, required at least 15~20 years to make more than 6 generations, and their offspring number is limited. To overcome such limitations, superovulation and in vitro fertilization have been developed. For superovulation, the number of produced embryos are not enough for commercialization and donor cows need rest period. This led to use of slaughterhouse ovary for in vitro fertilization, but it is impossible to repeat the collection from the same individual and it only can improve the genetic merits of offspring for one generation. Production of embryos using Ovum Pick-Up (OPU) technique, where oocytes can be repeatedly collected from living elite donor, might overcome these limitations. In this study, we investigated the possibility of using OPU technique from donors at different age and different session periods for mass-embryo-production. Oocytes were collected from 26 donor cows twice per week, 3 - 4 months per year, between 2013 and 2016. Results showed that, the average number of embryo produced in first year used donor was significantly higher than that in second year used donor ($3.89{\pm}2.85$ vs $3.29{\pm}2.70$), however, there was no significant difference between third year used donor ($3.51{\pm}3.32$) and other groups. Taken together, our data showed that repeated using of donor up to three years is possible for in vitro embryo mass-production. Moreover, OPU can be used as suitable embryo producing technique for livestock breed improvement.