• Asian-Australasian Journal of Animal Sciences
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• v.27 no.10
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• pp.1373-1380
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• 2014

The thyroid hormone responsive protein (THRSP) gene is a functional gene that can be used to indicate the fatty acid compositions. This study investigates the relationships of exonic single nucleotide polymorphisms (SNPs) in the THRSP gene and fatty acid composition of muscle fat and marbling score in the 612 Korean cattle. The relationships between fatty acid composition and eight SNPs in the THRSP gene (g.78 G>A, g.173 C>T, g.184 C>T, g.190 C>A, g.194 C>T, g.277 C>G, g.283 T>G and g.290 T>G) were investigated, and according to the results, two SNPs (g.78 G>A and g.184 C>T) in exon 1 were associated with fatty acid composition. The GG and CC genotypes of g.78 G>A and g.184 C>T had higher unsaturated fatty acid (UFA) and monounsaturated fatty acid (MUFA) content (p<0.05). In addition, the $ht1^*ht1$ group (Val/Ala haplotype) in a linkage disequilibrium increased MUFAs and marbling scores for carcass traits (p<0.05). As a result, g.78 G>A and g.184 C>T had significantly relationships with UFAs and MUFAs. Two SNPs in the THRSP gene affected fatty acid composition, suggesting that GG and CC genotypes and the $ht1^*ht1$ group (Val/Ala haplotype) can be markers to genetically improve the quality and flavor of beef.

• Korean Journal of Agricultural Science
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• v.47 no.3
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• pp.667-672
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• 2020

It is well known that intensive selection caused a decline in reproductive performance in dairy cattle. Interestingly, the reproductive performances including fertility and calving interval of Korean native beef cattle have declined in the last 20 years, suggesting that a breeding program focusing on carcass weight and intramuscular fat may affect the reproductive physiology in Korean native beef cattle, too. In this study, we analyzed the calving interval (CI) and selection index (SI) based on genome-wide association studies (GWAS) of Hanwoo cows for seven years (2013 - 2019). Multiparous cows (4.5 ± 0.11) were analyzed, which were bred by artificial insemination (AI). We first examined the distribution of the AIs and calving dates. About 40% of the AIs were carried out in May to June and October to December; subsequently, calving was observed from March to April and August to October, respectively, indicating the cows were seasonally bred. No correlation between CI and SI was found (y = 0.0459x - 17.64; R² = 0.0356), but the ratio of cows with a positive SI was higher in the longer CI group compared to the shorter group, suggesting that the selection for meat quality and quantity may affect the reproductive performances. In addition, the average value of SI was - 3.42 in the CI < 400 while + 5.79 in the CI > 400 although the values were not statistically significant. However, our results suggest that reproductive indices such as fertility and CI should be considered for sustainability in the Hanwoo breeding selection program.

• Asian-Australasian Journal of Animal Sciences
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• v.15 no.2
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• pp.279-282
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• 2002

Twenty six male Hanwoo (Korean cattle) carcasses were measured for pH, temperature and instrumental color changes of loins during 24 h post-mortem carcass chilling at $4^{\circ}C$ in the cooler. The average internal temperature of loins was about $5^{\circ}C$ after 24 h of chilling, and with the exclusion of those with an ultimate pH>6.0 (dark-cutters), the average pH value was 5.5. When all carcasses were considered for the partial correlation coefficient between color and pH, with the temperature effect excluded, CIE $L^*$, $a^*$ and $b^*$ seemed to be affected significantly by pH during chilling process (p<0.001). However, when carcasses with dark-cutting condition were excluded, the correlation coefficients were much lower. In contrast, when the partial correlation coefficients between color and temperature, excluding the effect of pH on them, were analyzed, the relationship between color and temperature did not change much after values of DFD (dark, firm, dry) beef were excluded. The results suggested that the known interrelationship of color and pH in chilled beef loins be mainly due to the influence of temperature on pH and color.

• Parasites, Hosts and Diseases
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• v.55 no.4
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• pp.457-460
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• 2017

Previous paleoparasitological studies of Joseon specimens established that the prevalence of Taenia infection was not much different from that of the early 20th century Korean population. As many of taeniases originally diagnosed as Taenia saginata in South Korea were revealed to be actually Taenia asiatica, which share a common intermediate host with T. solium (the pig), Joseon people must have ingested raw pork frequently. However, the current examination of extant Joseon documents revealed that the population ate significant amounts of beef even if the beef ban was enforced; and pork was not consumed as much as we thought. Considering the meat consumption pattern at that time, Joseon people should have been infected by T. saginata more frequently than T. asiatica. This may suggest a low prevalence of T. saginata metacestodes in cattle compared to that of T. asiatica metacestodes in pigs, possibly due to the traditional way of rearing pigs (using human feces). This letter gives us a chance to reconsider the existing preconception about parasitic infections in Korean history though we are still hard to accurately estimate the historical patterns of taeniases at this stage.

• Asian-Australasian Journal of Animal Sciences
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• v.31 no.3
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• pp.327-334
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• 2018

Objective: The objective of the present study was to validate genes and genomic regions associated with carcass weight using a low-density single nucleotide polymorphism (SNP) Chip in Hanwoo cattle breed. Methods: Commercial Hanwoo steers (n = 220) were genotyped with 20K GeneSeek genomic profiler BeadChip. After applying the quality control of criteria of a call rate ${\geq}90%$ and minor allele frequency (MAF) ${\geq}0.01$, a total of 15,235 autosomal SNPs were left for genome-wide association (GWA) analysis. The GWA tests were performed using single-locus mixed linear model. Age at slaughter was fitted as fixed effect and sire included as a covariate. The level of genome-wide significance was set at $3.28{\times}10^{-6}$ (0.05/15,235), corresponding to Bonferroni correction for 15,235 multiple independent tests. Results: By employing EMMAX approach which is based on a mixed linear model and accounts for population stratification and relatedness, we identified 17 and 16 loci significantly (p<0.001) associated with carcass weight for the additive and dominant models, respectively. The second most significant (p = 0.000049) SNP (ARS-BFGL-NGS-28234) on bovine chromosome 4 (BTA4) at 21 Mb had an allele substitution effect of 43.45 kg. Some of the identified regions on BTA2, 6, 14, 22, and 24 were previously reported to be associated with quantitative trait loci for carcass weight in several beef cattle breeds. Conclusion: This is the first genome-wide association study using SNP chips on commercial Hanwoo steers, and some of the loci newly identified in this study may help to better DNA markers that determine increased beef production in commercial Hanwoo cattle. Further studies using a larger sample size will allow confirmation of the candidates identified in this study.

• Asian-Australasian Journal of Animal Sciences
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• v.29 no.2
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• pp.184-194
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• 2016

The peroxisome proliferator-activated receptor gamma ($PPAR{\gamma}$) gene plays an important role in the biosynthesis process controlled by a number of fatty acid transcription factors. This study investigates the relationships between 130 single-nucleotide polymorphisms (SNPs) in the $PPAR{\gamma}$ gene and the fatty acid composition of muscle fat in the commercial population of Korean native cattle. We identified 38 SNPs and verified relationships between 3 SNPs (g.1159-71208 A>G, g.42555-29812 G>A, and g.72362 G>T) and the fatty acid composition of commercial Korean native cattle (n = 513). Cattle with the AA genotype of g.1159-71208 A>G and the GG genotype of g.42555-29812 G>A and g.72362 G>T had higher levels of monounsaturated fatty acids and carcass traits (p<0.05). The results revealed that the 3 identified SNPs in the $PPAR{\gamma}$ gene affected fatty acid composition and carcass traits, suggesting that these 3 SNPs may improve the flavor and quality of beef in commercial Korean native cattle.

• Food Science of Animal Resources
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• v.30 no.6
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• pp.905-909
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• 2010

Two sets of data on carcass traits and beef cut parameters were used to investigate the relationships between carcass and beef cut measurements, which can be used to make predictions of retail cut percentages. One set had a total of 1,141 measurements of Hanwoo cattle of three different sex origins, which were slaughtered in an abattoir located at the National Institute of Animal Science, RDA, Korea from 1996 to 2008. To develop prediction models for retail cut percentage with higher accuracies than the current model, another set consisting of a total of 13,389 records of carcass and beef cut traits were collected from 30 abattoirs and butcheries in Korea from 2008 to 2009. Bulls yielded heavier and leaner carcasses than steers. High correlation coefficients were estimated between amount of body fat and percent retail cut (-0.82) as well as between back fat thickness (BF) and percent retail cut (-0.62). The amount of retail cut, however, was highly correlated with body weight before slaughter (BW, 0.95) or with cold carcass weight (CWT, 0.94). Relationships between percent retail cut and measurable beef yield traits, BF, loin eye area (LEA) or CWT varied by sex class, which must be considered for development of a prediction model with high accuracy. Models of data for all breeds and sexes fit the effects of breed, sex, and interaction of abattoir by butchers, whereas models of data for each breed and sex fit the effect of interaction of abattoir by butcher only. Due to possible future changes in back fat control, we performed a log transformation of BF. Our new models fit better than the currently used model.

• Korean Journal of Veterinary Service
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• v.22 no.4
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• pp.325-347
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• 1999

This study was conducted to investigate the epidemiological, clinicopathological, microbiological, pathological observations and other tests from sudden death in feedlot cattle at the region of Sarari in Korea during the period from 1994 to 1999. Massive or sporadic occurrence of sudden death has been observed in 101 heads of 47 farmhouse. There were 20.8% in spring, 29.7% in summer, 16.8% in autumn, 32.7% in winter, and 62.3% in reproductive, 27.7% in growing, 5.0% in beef cattle, 5.0% in calf in prevalence of sudden death in cattle. Enterotoxemia(88.0%), pneumonia(3.5%), intestinal diarrhea(3.5%), liver abscess(1.5%) and indigestion(1.5%) were detected from 67 heads of sudden death cattle. In clinical observations, cattle were generally died of sudden recumbency with convulsions followed anorexia, depression, ataxia, muscular tremor, tachycardia and dyspnea without any premonitory symptoms. Epidemiological surveys showed no evidence that other factors such as pesticide, insecticide, fertilizer, chemical drug3 and those of others caused sudden death. Macroscopically, there were coagulation disorders of blood, congestion, edema and haemorrhage of lung, congestion and haemorrhages, watery and blood-tinged contents of small intestine. Histopathologically, we observed pulmonary congestion and haemorrhage, necrotic intestinal mucosa accompanied with haemorrhage and congestion, and also increased globule leukocytes between bronchial epithelia with mild pneumonia. Clinicopathologically, only elevation of blood glucose and aspartate aminotransferase(AST) was detected. Magnesium and calcium deficiency were not detected, but parasites were detected highly in normal and dead cattles. Microbiologically, Clostridium(Cl) pefringens were detected from small intestinal contents of 94% (63/67) of sudden death cattle and 51%(51/101) of slaughter cattle, and the population were $10^{6-8}$/cfu/$m\ell$ after 16~32 hours. Consequently, it was proved that the cause of death in cattle was enterotoxemia. Pathogenic test of mouse and goat inoculated with Cl perfringens type A toxin has been demonstrated as similar observation to natural cases. In antimicrobial susceptibility test, ampicillin, bacitracin, polymycin, cephalothin, penicillin, choramphenicol, erythromycin, tetracycline were highly susceptible, and amikacin, gentamicin, kanamycin, neomycin, streptomycin, sulfamethoxine, sulfamethazine were resistant. Cl perfringens were resisted for 4 hours in 3% formalin, 20 minutes in 4% phenol, 20 minutes in 0.5% mercuric chloride and 40 minutes in 0.1% sodium hydroxide, respectively. The useful method to prevent from occurrance of enterotoxemia in feedlot cattle was a dietary administration of antibiotics and miyari acid.

• Asian-Australasian Journal of Animal Sciences
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• v.26 no.2
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• pp.151-156
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• 2013

Hanwoo (Also known as Korean native cattle; Bos taurus coreanae) have been used for transportation and farming for a long time in South Korea. It has been about 30 yrs since Hanwoo improvement began in earnest as beef cattle for meat yield. The purpose of this study was to determine the trend of improvement as well as to estimate genetic parameters of the traits being used for seedstock selection based on the data collected from the past. Hanwoo proven bulls in South Korea are currently selected through performance and progeny tests. National Hanwoo genetic evaluations are implemented with yearling weight (YW), carcass weight (CW), eye muscle area (EMA), backfat thickness (BF) and marbling score (MS). Yearling weights and MS are used for selecting young bulls, and EMA, BF, and MS are used for selecting proven bulls. One individual per testing room was used for performance tests, and five individuals per room for progeny tests. Individuals tested were not allowed to graze pasture, but there was enough space for them to move around in the testing room. Feeds including roughages and minerals were fed ad libitum, and concentrates were provided at the rate of about 1.8% of individual weight. Overall means of the traits were $352.8{\pm}38.56$ kg, $335.09{\pm}44.61$ kg, $77.85{\pm}8.838\;cm^2$, $8.6{\pm}3.7$ mm and $3.293{\pm}1.648$ for YW, CW, EMA, BF and MS. Heritabilities estimated in this study were 0.30, 0.30, 0.42, 0.50 and 0.63 in YW, CW, EMA, BF and MS, respectively, which are similar to results from previous research. Yearling weight was 315.54 kg in 1998, and had increased to 355.06 kg in 2011, resulting in about 40 kg of improvement over 13 yrs. YW and CW have improved remarkably over the past 15 yrs. Breeding values between 1996 and 2000 decreased or did not change much, but have moved in a desirable direction since 2001. These improvements correspond with the substantial increase in use of animal models since the late 1990s in Korea. Hanwoo testing programs have practically contributed to the improvement in aspects of quality and quantity. In sum, the current selection system is good enough to accommodate circumstances where fewer sires are used on many more cows. Although progeny tests take longer and cost more, they seem to be appropriate under the circumstances of the domestic market with its higher requirement for better meat quality. Consequently, accumulative data collection, genetic evaluation model development, revision of selection indices, as well as cooperation among farms, associations, National Agricultural Cooperative Federation, universities, research institutes, and government agencies must be applied to the Hanwoo selection program. All these efforts will assist the domestic market to secure a competitive position against imported beef under Free Trade Agreement trade system and will provide farmers with higher profits as well as the public with a higher quality of beef.

• Korean Journal of Veterinary Research
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• v.49 no.4
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• pp.309-317
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• 2009

The present study describes an investigation on an epidemic of Tuberculosis (TB) which has been occurred among dairy cattle farms in Jeongeup, Jeollabuk-do since 2007. The investigation was performed in three ways as follows: 1. Collecting information about bovine TB outbreaks using investigation reports, an on-the-spot and tracing-back investigations; 2. Analyzing the outbreak pattern; 3. Establishing hypothesis and performing statistical analysis on potential risk factors. In the early 2000s, TB outbreaks were sporadically reported in beef cattle, and only a small number ($1{\sim}2$) of reactors was confirmed in each of outbreak farms. The number of TB outbreaks has been suddenly increased from 2007, mainly in dairy cattle farms. And these outbreaks were temporarily clustered during the period, from March 2007 to April 2009 (relative risk, RR = 13.7, p < 0.001). And two spatial clusters of which radiuses were 0.3 km (RR = 6.9, p < 0.001) and 0.9 km (RR = 3.6, p < 0.01). The analysis to find risk factors was performed on 99 dairy farms (21 outbreaks), which are located in the most seriously affected village during 2007-2009. Middleman (odds ratio, OR = 47.4, p < 0.05) and raw milk collecting system (OR = 6.9, p < 0.05) were recognized as with the highest association. Considering the fact that all the outbreak farms except one had their own manure composting tank, it might be that the manure containing pathogen was leaked from tank and transmitted to other farms by fomites such as middleman or raw milk collecting system.