• 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.

• Journal of Embryo Transfer
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• v.32 no.1
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• pp.1-8
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• 2017

Cryopreservation of germ cells from genetically proven animals could be a source of restoration tools from the risk of extinction or disappearance of wanted characteristics. Using frozen semen, the genetic gains of Korean native cattle have been increased greatly for 70 years. The preservation of genetic resources as a form of frozen semen straw has limited availability due to the numbers. To circumvent this weakness of frozen semen, we tested two re-freezing methods with different initial thawing temperatures using frozen Korean proven semen and rare breed semen from albino, black and chikso breeders. It has been known that human sperm could resist to cryo-damages by repeated freeze-thaw cycles, but not for Korean proven bulls number (KPN) or for rare breeds. Total 7 frozen semem from brindled(2), black(1), Korean Albino(2) and KPN(1) bulls were used for our research. After thawing straws under $5^{\circ}C/2min$ or $37^{\circ}C/40sec$ with low temperature water bath and thermo jug, spermatozoa were re-diluted with triladyl diluents after first thawing and re-frozen. Sperm motilities were compared between animals and treated groups after re-thawing. Mean values of motility and viability of refrozen/thawed sperm for expansion of the number of straws were significantly higher in $5^{\circ}C$ than in $37^{\circ}C$ (P < 0.05). However, the activity of viable sperm thawed at $5^{\circ}C$ was significantly decreased before refreezing. It is estimated that re-freezing of frozen semen from rare Korean native cattle is possible with resistant properties of survived spermatozoa.

• Korean Journal of Poultry Science
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• v.48 no.2
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• pp.69-80
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• 2021

We conducted a 4 × 4 diallel cross-mating test using 934 chickens from four grandparent stock lines to develop a new synthetic breed of Korean native chicken. The mean values, combining ability, and reciprocal effects on survival rate, body weight, and hen-day egg production were analyzed. In phenotypes, most chickens have yellowish-brown, reddish-brown and mixed color feathers. The average survival rate was 86.8±12.3%, with the highest in YH combination. Specific combining ability (SCA) had a greater effect on survival rate than general combining ability (GCA), and the SCA of HY combination was the highest. The 16 cross-combinations were distinctly divided into three weight groups according to their genetic characteristics. At 12 weeks of age, GCA showed a greater effect on weight than SCA, and the SCA of FH combination was the highest. The age at first egg laying was 157 days, and the crosses reached sexual maturity faster than the pure lines. The egg production rate was highest in SY at 79.5±2.1%. The GCA and SCA for hen-day egg production were similar, and the SCA was highest in the HS and FY combinations. The reciprocal effect showed that the offspring's egg production rate was high when S and Y were maternal parents in almost all combinations. In conclusion, FH and HF combinations, which have excellent growth performance, are the most desirable paternal parent stock strains, and FY, FS, HY, and SY combinations, which have excellent laying performance with moderate weight, are the preferred maternal strains.

• Korean Journal of Poultry Science
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• v.50 no.4
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• pp.241-249
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• 2023

Following the Animal genetic resource for food and agriculture (AnGR) is considered as an independent resource for the possessing country, ensuring the sovereignty of AnGR is important. The present study investigated the growth and egg production performance of six breed enrolled in DAD-IS for the purpose of securing scientific data on AnGR in Korea. A total of 323 chickens (female 181, male 142) were used in this study, with the following six breeds: Korean Leghorn (LEG), Gyeongbuk Araucana (ARA), Korean native chicken (KNC), Korean Ogye (Ogye), Hyunindak (HIL), Heongseongyakdak (HYD). The body weight of male ARA from hatching to 32 weeks of age was the highest among the breeds, and LEG and Ogye were relatively lower (P<0.0001, excluded body weight data of HYD). The body weight of female ARA was the highest and HYD was significantly the lowest among the female chicken breeds (P<0.0001). The laying percentage was the highest in LEG and was the lowest in HYD among the breeds (P<0.0001). The average egg weight from 20 to 40 weeks of age was the highest in ARA, followed by LEG and was the lowest in Ogye (P<0.0001), and the adapted breed including LEG and ARA was higher than indigenous breed (P<0.05). Egg mass production was the highest in Korean Leghorn. Collectively, these results show that ARA has the best growth ability, and LEG has the best egg production performance among the used breeds. This suggests that the adapted breed with high commercial performance is important AnGR in Korea.

• Asian-Australasian Journal of Animal Sciences
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• v.16 no.7
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• pp.952-961
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• 2003

In the first part of the study, rates of estrus occurrence and success of A.I. service in the Thai-native and Friesian crossbred, and purebred Friesian cows fed in the National Dairy Training and Applied Research Institute in Chiang Mai, Thailand were traced monthly throughout a year. An electric fan and a water sprinkler cooled the stall for the purebred cows during the hot season (March-September). Both rates in pure Friesians were at their highest in the cold-dry season (October- February), but they decreased steadily during the hot-dry season (March-May) and were at their lowest in the hot-wet season (June-September). Seasonal change of a similar pattern was observed in the incidence of estrus, but not in the success rate of insemination in the crossbred cows. By the use of reproductive data, compiled in the same institute, on the 75 % cross- and purebred Friesian cows, and climatological data in Chiang Mai district, effects of ambient temperature and humidity on the reproductive traits of cows were examined by regression analysis in the second half of the study. Significant relationships in the crossbred, expressed by positive-linear and parabola regressions, were found between reproductive parameters such as days to the first estrus (DTFE), A.I. service (DTFAI), and conception, the number of A.I. services required for conception and some climatic factors. However, regarding this, no consistent or intelligible results were obtained in purebred cows, perhaps because electric fans and water sprinklers were used for this breed in the hot season. Among climatic factors examined, the minimum temperature (MINT) in early lactation affected reproductive activity most conspicuously. As the temperature during one or two months prior to the first estrus and A.I. service rose, DTFE and DTFAI steadily became longer, although, when MINT depleted below $17-18^{\circ}C$, the reproductive interval tended to be prolonged again on some occasions. The maximum temperature also affected DTFE and DTFAI, but only in limited conditions. The effect of humidity was not clear, although the inverse relationship between DTFE and minimum humidity during 2 months before the first estrus in the crossbred seemed to be significant. Failure to detect any definite effect of climate on the reproductive traits of pure Friesians seemed to indicate that forced ventilation by electric fans and water sprinklers were effective enough to protect the reproductive ability of this breed from the adverse effects of a hot climate.

• Journal of Animal Science and Technology
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• v.51 no.3
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• pp.193-200
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• 2009

The pork from black-coated pigs is famous among-consumers for better eating quality. The loci affecting black coat color was identified in pig chromosome 6 in which several genetic effects on pork quality have been reported. The melanocortin 1 receptor (MC1R) gene is a major gene which plays a key role in regulation of eumelanin (black/brown) and phaeomelanin (red/yellow). In this study, the MC1R gene polymorphism was analyzed for pig breed determination and genetic association with pork quality traits. MC1R Ala243Thr variation was analyzed to determine a specific genotype for four commercial pig breeds (Landrace, Yorkshire, Berkshire and, Duroc) and a Korean native pigs (KNP). Then we developed original KNP-specific DNA markers to determine the pork from black-coated pigs using MC1R DNA sequences. The total length of the MC1R coding sequence ranged 1451bp in KNP. KNP had the 0201 allele pertaining to $E^{D1}$ but some of the KNP had the $E^P$ allele, probably reflecting the geneticintrogression of $E^P$ allele into KNP. Furthermore, a relationship between Leu102Pro single nucleotide polymorphism (SNP) genotype and pork quality phenotype were analyzed in F2 reciprocal-crossbred population between KNP and Yorkshire. Association analysis indicated that the allele of the MC1R gene has no effect on pork quality. These results suggest that black coat-color is not directly associated with preferred pork quality, but the black-coat color pig breed may have other genetic components for superior pork quality.

• Asian-Australasian Journal of Animal Sciences
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• v.18 no.9
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• pp.1348-1352
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• 2005

Most breeds of sheep in Iran are adapted to their agro ecological niches where it is likely that they were also artificially selected by their owners. In general, most of sheep breeds are multipurpose producing lambs, wool and milk. To compare the physical and chemical composition of the carcasses of ten Iranian native fat-tailed sheep breeds, 243 male lambs (6-7 months of age) of ten fattailed, Iranian breeds of sheep, Sanjabi (S), Ghezel (G), Afshari (A), Mehrabani (M), Lori (L), Lori Bakhtiari (LB), Kordi Khorasan (K), Sangesari (Sa), Baluchi (B) and Chal (C) were studied. Lamb breed group had a significant (p<0.05) effect on all the carcass traits measured. The LB and C lambs showed the same live weight which was significantly (p<0.05) higher than the other breeds. Carcass dressing- out percentage in S lambs was lowest (p<0.05), but not different from G lambs. K and Sa breeds showed the highest (p<0.05) carcass dressing-out percentage. The S lambs had the highest (p<0.05) lean meat percent. Lean meat percentage was not significantly (p>0.05) different in the G, A, M and C breeds. The Sa and K breeds showed the lowest lean meat percent. The S lambs showed the lowest (p<0.05) fat percent in their carcass, while K and Sa showed the highest (p<0.05). Subcutaneous fat in K, Sa and B was higher (p<0.05) than the other breeds. Lambs of S, G, A and M breeds had the lowest subcutaneous fat in their carcasses (p>0.05). Intramascular fat was significantly (p<0.05) lower in M, S and C despite the fact that this values were highest in B and K lambs. The K and Sa breeds had highest fat-tail percentage (p<0.05) in their carcass, whereas S and G showed lowest. Lambs of G, S and A breeds had higher bone percent than other breeds (p<0.05). Lowest bone percent (p<0.05) was seen in K and Sa lambs. The carcass moisture percent was not significantly (p>0.05) different in S, G, A, M, L and C breeds. M lambs showed the lowest crude protein percentage and S breed the highest (p<0.05). There were no significant (p>0.05) differences among other lamb breeds for this trait. Chemical fat percentage was the same in S, G, A, C and M breeds, but significantly (p<0.05) lower from LB, K, Sa and B. Ash percent in S, G and A had no significant (p>0.05) difference. According to higher lean meat and lower fat percentages in the carcass, the ranking of breeds would be S, G, A, M and C.

• Molecules and Cells
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• v.38 no.5
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• pp.466-473
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• 2015

Over the last 30 years, Hanwoo has been selectively bred to improve economically important traits. Hanwoo is currently the representative Korean native beef cattle breed, and it is believed that it shared an ancestor with a Chinese breed, Yanbian cattle, until the last century. However, these two breeds have experienced different selection pressures during recent decades. Here, we whole-genome sequenced 10 animals each of Hanwoo and Yanbian cattle (20 total) using the Illumina HiSeq 2000 sequencer. A total of approximately 3.12 and 3.07 billion sequence reads were mapped to the bovine reference sequence assembly (UMD 3.1) at an average of approximately 10.71- and 10.53-fold coverage for Hanwoo and Yanbian cattle, respectively. A total of 17,936,399 single nucleotide polymorphisms (SNPs) were yielded, of which 22.3% were found to be novel. By annotating the SNPs, we further retrieved numerous nonsynonymous SNPs that may be associated with traits of interest in cattle. Furthermore, we performed whole-genome screening to detect signatures of selection throughout the genome. We located several promising selective sweeps that are potentially responsible for economically important traits in cattle; the PPP1R12A gene is an example of a gene that potentially affects intramuscular fat content. These discoveries provide valuable genomic information regarding potential genomic markers that could predict traits of interest for breeding programs of these cattle breeds.

• Food Science of Animal Resources
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• v.24 no.3
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• pp.246-252
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• 2004

The objective of this study was to determine the changes of physico-chemical characteristics in crossbred pigs (Korean native breed ${\times}$ Landrace breed) by carcass grade. Research was conducted on 250 pigs divided into 5 carcass grade groups. Cooking loss have significantly (p<0.05) higher in higher carcass grade. However, water content, crude fat, pH and shear force have no difference. In meat color, a＊ was significantly (p<0.05) higher in C and D grade, whereas A grade was lower than those of others. L＊ and b＊ did not different among the carcass grades. In fat color, A and E grade were significantly (p<0.05) higher in b＊ and, C was lower than those of others. Adhesiveness and Gumminess of cooked meat were significantly (p<0.05) higher when carcass grade was higher. However hardness, cohesiveness, springiness and brittleness were not different among the carcass grades. Palmitic acid was significantly (p<0.05) higher in higher carcass grades and, saturated fatty acid/unsaturated fatty acid ratio was lower, whereas other fatty acids compositions had no difference among the carcass grades.

• Korean Journal of Poultry Science
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• v.41 no.1
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• pp.29-37
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• 2014

The Feather Color of chicken is considered as most obvious, and the purpose of this study is to identify the genotype following the SNP of MC1R, MITF and TYRP1, which are genes related to Feather Color, and develop a SNP marker that can be classified per breed. When a haplotype is observed through the combination of markers, a Korean Native Chicken can especially be distinguished when it is a CGG type in the SNP combination of the MC1R gene. In case of the TAG, TGG and TAA types, only Araucana was identified, and for the CAA type, Leghorn could specifically be distinguished. In the SNP combination of TYRP1 gene, only Leghorn was differentiated in case of the TTTCA and CCTCA types, and only Silky Fowl was identified in case of the CTTTA type. The SNP combination of MC1R gene enabled for Korean Native Chicken, Leghorn, and Araucana to be distinguished and each of the SNP and combination of TYRP1 gene allowed for all 4 breeds to be classified. If many researches are conducted about genetic polymorphism between breeds, then it is considered that the differences between breeds will be understood from a molecular biological aspect instead of simply distinguishing the breeds through Feather Color.