• Current Research on Agriculture and Life Sciences
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• v.4
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• pp.102-108
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• 1986

This study was carried out to examine the effects of seasonality, age, abnormalities of reproductive tract and the frequency of superovulatory treatments on the superovulatory responses and rate of pregnancy in repeat breeder for embryo transfer. Thirty eight eggs were obtained from 6 donors by flushing the uterine horns and 33 embryos were transfered to 33 recipients. (29 holstein heifers, 3 holstein cows and 1 Korean native heifer). From this study, the following results could be obtained: 1. It seemed that spring (Feb.-Apr.) was the better season than any others to produce good embryos. Rate of pregnancy decreased significantly after August because of low heating rate. 2. Rate of pregnancy in the cows with normal reproductive tract showed much better superovulatory responses (80%) than the cows with abnormal reproductive tract (33%), as expected. 3. 8 years old cows produced higher rater of pregnancy than 4 years old cow (79.3 vs 50), and also in superovulatory responses, 8 years old cows showed slightly better results than 4 years old cow. 4. The number of ovulated eggs and rate of pregnancy in the repeated superovulatory treatment more than once were 41 eggs and 85.7%, and those of the donors treated the first superovulatory treatment were 32 eggs and 68.4%, respectively. 5. These results are showing the possibility that utilizing the repeat breeders as donors in embryo transfer could be able to elevate their economic values.

• Korean Journal of Veterinary Service
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• v.44 no.4
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• pp.227-237
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• 2021

Artificial insemination of Korean native cattle (KNC) is the predominant method for breed improvement. However, industrialization of embryo production and transfer is necessary to utilize the genetic potential of KNC. The aim of this study was to examine associations between KNC donor cows and ovum pick-up (OPU) conditions, in-vivo oocyte recovery, and embryo development. Oocyte recovery and blastocyst development rates were higher at 50 and 60 mmHg OPU vacuum pressure than at 40 mmHg, which was, however, not significant. Regarding follicle growth, injection of 500 ㎍ GnRH 36 hours before OPU significantly increased the number of OPU oocytes from an average of 4.6 to 7.6 (P<0.05); no significant difference in embryo development rates was observed. Significant differences were observed in the numbers of OPU oocytes, embryo development rates, and transplantable blastocysts per individual among nine KNC donors (P<0.05). Furthermore, although there was no difference in OPU oocyte recovery intervals in approximately 2~8 weeks, the number of recovered oocytes significantly decreased at the 12-week interval (P<0.05); there was no difference in embryo development rates. The number of oocytes and embryonic development rates only tended to decrease until the seventh OPU session, but decreased significantly until the eighth session (P<0.05). The average pregnancy rate after transfer of OPU-derived in-vitro embryos into recipient cows was 41.8%. To improve the efficiency of OPU egg recovery and in-vitro embryo production, considering KNC donor characteristics, vacuum pressure of 60 mmHg, GnRH pretreatment to induce follicle growth, and effective OPU egg recovery up to seven times at intervals of 2~4 weeks appears to be most suitable. This study may facilitate the industrialization of KNC embryo production and transfer using high-quality cows.

• Asian-Australasian Journal of Animal Sciences
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• v.33 no.7
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• pp.1202-1208
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• 2020

Objective: The aim of this study was to identify a distribution pattern of meat quality grade (MQG) as a function of carcass yield index (CYI) and the gender of Hanwoo (bull, cow, and steer) to determine the optimum point between both yield and quality. We also attempted to identify how pre- and post-deboning variables affect the gender-specific beef quality of Hanwoo. Methods: A total of 31 deboning variables, consisting of 7 pre-deboning and 24 post-deboning variables from bulls (n = 139), cows (n = 69), and steers (n = 153), were obtained from the National Institute of Animal Science (NIAS) in South Korea. The database was reconstructed to be suitable for a statistical significance test between the CYI and the MQG as well as classification of meat quality. Discriminant function analysis was used for classifying MQG using the deboning parameters of Hanwoo by gender. Results: The means of CYI according to 1+, 1, 2, and 3 of MQG were 68.64±2.02, 68.85±1.94, 68.62±5.88, and 70.99±3.32, respectively. High carcass yield correlated with low-quality grade, while high-quality meat most frequently was obtained from steers. The classification ability of pre-deboning parameters was higher than that of post-deboning parameters. Moisture and the shear force were the common significant parameters in all discriminant functions having a classification accuracy of 80.6%, 71%, and 56.9% for the bull, cow, and steer, respectively. Conclusion: This study provides basic information for predicting the meat quality by gender using pre-deboning variables consistent with the actual grading index.

• 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.48 no.2
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• pp.187-190
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• 2008

Eosinophilic myositis lesions are characterized by severe eosinophil infiltration along muscles of affected animals. The exact cause of the lesion remains controversial and the carcass is condemned once this lesion is seen during meat inspection. A cow slaughtered in Chonbuk province, Korea was observed to have disseminated pale foci throughout the musculature; meat samples were obtained and macroscopically investigated. Cut ends of neck and thigh muscle tissues showed variably sized, multifocal pale white-grayish nodular lesions. Histopathological examination consistently revealed inflammatory lesions with adjacent infiltration of eosinophilic granulocytes and focal necrotic calcification. However, no parasites, including Sarcocystis sp., could be discerned in the affected carcass. This case was diagnosed as idiopathic eosinophilic myositis in cattle.

• Reproductive and Developmental Biology
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• v.37 no.1
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• pp.23-27
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• 2013

This study was carried out to investigate the influence of artificial insemination (AI) failure in 1,619 Korean native cows at Gangwon East area, Korea. The average AI failure rate was 37.02% in the cows and the highest rate was 40.85% in Yangyang-city. Based on the parity in the cows, the AI failure rate was 49.14% and 29.91% in the first and fifth parity cows, respectively. Whereas cows until fifth parity were decreased in AI failure, cows with sixth or more parity showed an upturning AI failure trends with the increasing of parity number. AI failure rate incidence according to the rump fat thickness measured by ultrasound was 28.9% and 33.4% at 5 mm to 10 mm and over than 15 mm, respectively. There was a positive correlation (0.2186) between AI failure rate of mother and that of their offspring cows. That is, offspring of dams with high AI failure rate showed also higher AI failure than those of dams having lower AI failure rate. In conclusion, these results indicate that the AI failure rate was closely related to the rump fat thickness, parity number, and conception rate of mother cows. In addition, these results might strengthen the basis to improve the reproductive performance in Korean native cows.

• Korean Journal of Veterinary Service
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• v.41 no.1
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• pp.9-13
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• 2018

The best way to prevent foot-and-mouth disease (FMD) constantly occurring in Korea will be vaccination. In this study, FMD vaccines were given to Korean native cattle (Hanwoo), dairy cattle, and pigs to investigate the antibody positive rate of FMD vaccine by age in year and month. Hanwoo, dairy cattle, and pigs showed antibody positive rates of 99.5%, 97.7%, and 95.9%, respectively. High antibody positive rates more than 95% were found in Hanwoo and dairy cattle. In particular, high antibody positive rates were found in Hanwoo and dairy cattle regardless of age. Pigs showed a relatively low antibody positive rate of 57.6% at 3 months of age and then constantly maintained a high antibody positive rate of above 95.0% after 4 months of age. As a result of this study, high antibody positive rates were found when regular FMD vaccination was given to newborn calves and piglets after FMD vaccination twice to them. Therefore, it is considered the most important to receive vaccination thoroughly according to vaccination plan in order to prevent FMD.

• Korean Journal of Environmental Agriculture
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• v.12 no.3
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• pp.239-246
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• 1993

In order to clarify the possible contamination of rice straw used as a crude feed for livestock, Korean native cattle and cow, by pesticides, the samples collected from 21 sites in Korea were analyzed by a multiresidue method for 10 pesticides with GLC to obtain the following results. 1. Detection limits were 0.001ppm in butachlor, 0.002ppm in chlorpyrifos, 0.003ppm in BPMC, pirimiphos-methyl and diazinon, 0.004ppm in fenitrothion, 0.005ppm in phenthoate, 0.009ppm in IBP, 0.015ppm in carbofuran, and 0.03ppm in carbaryl. 2. In recovery tests, 73-101% of the pesticides applied were recovered, the recovery being low in carbofuran and chlorpyrifos. 3. Butachlor, 2-chloroacetanilide herbicide, and BPMC, carbaryl, and carbofuran, carbamate insecticides, were not detected in any sample. 4. In organophosphorus insecticides, the amounts of fenitrothion in sample No. 1, 2, 4, 5, 7, 12, 20 and 21 were in the range of 0.01-0.05ppm, those of phenthoate detected in sample No. 10 and 12 were 0.4 and 0.17ppm, respectively, and those of IBP in all samples, with the exception of sample No. 7, 12, 16, 17, 20, and 21, were in the range of 0.01-0.20ppm. The residues of chlorpyrifos, diazinon, and pirimiphos-methyl were not detected.