• Journal of Embryo Transfer
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• v.15 no.1
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• pp.77-83
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• 2000

The purpose of this study was to develop a breeding technique to increase Hanwoo of superior characteristics. In the present study, reproductive status of Hanwoo such as size of farm, breeding system and gestationi length was investigated. In addition, effect of low dose administration of prostaglandin F2$\alpha$(PGF2$\alpha$) on luteolysis was examined. The size of farm was classified by the total number of cows and the number of breeding stocks, respectively. The distribution of herd size of < 5, 6~10, 11~30, 31~50 and > heads was 31%, 15%, 39%, 4% and 11%, respectively. Furthermore, the distribution of breeding stock size of <5, 6~10, 11~30, 31~50 and > 50 heads was 36%, 28%, 31%, 3% and 3%, respectively. Average parity was 2.1 in breeding stock. In breeding pattern, artificial in semination(A.I), estrus synchronization-A.I and natural mating was 92.7%, 2.4% and 4.9% respectively. Gestational length of Hanwoo was ranged 253~316 days (average length : 285 days) after estrus( estrus=0). To induce luteolysis, PGF2$\alpha$ was injected into ovarian parenchyma by a modified ovarian injector. The effect of administration of 6mg PGF2$\alpha$ on luteolysis and estrus induction was betweer (P<0.01) when PGF2$\alpha$ was administered into ovarian parechyma than when administered intramuscluarly (71 vs. 91%). When PGF2$\alpha$ was injected into ovarian parenchyma, a decreased concentration to 3 mg did not significantly decreaed its luteolytic effect(92%). When AI was performed following PGF2$\alpha$ treatment, the intraovarian injection group yielded a higher pregnancy rate(69 vs. 88%) than the IM injection groups, regardless of the dosage. In conclusion these results suggest that increasing herd size and regular reproductive management are needed to improve reproductive efficiency in Hanwoo industry. Furthermore, intraovarian administration of PGF2$\alpha$ is effective way to induce luteolysis compared with intramuscular injection.

• Journal of The Korean Society of Grassland and Forage Science
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• v.32 no.4
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• pp.387-396
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• 2012

A study was conducted to determine the dietary effects of Na-bentonite (NaB) and probiotics on meat characteristics and health of Hanwoo steers fed rice straw as a sole roughage source. A total of 24 growing Hanwoo steers (avg BW 232 kg) were assigned to two treatments which included a control diet (concentrate mix and rice straw) and a treatment diet (control diet + 0.5-1.0% NaB + 0.5-1.0% probiotics. The diets were fed for 22 months up to the time the animals were slaughtered. Dietary treatment increased (p<0.05) concentrations of trace minerals such as Zn, Cu, and Fe in the longissimus muscle compared to the control. The treatment diet did not affect cold carcass weight, yield traits such as backfat thickness, longissimus muscle area, yield index, yield grade and quality traits such as marbling score, meat color, fat color, texture, maturity and quality grade. Blood profiles of growing steers were within the normal ranges for healthy cattle. In conclusion, feeding a combination of clay mineral and probiotics to Hanwoo steers fed rice straw as a sole roughage source could have a desirable effect on improving trace mineral retention in longissimus muscle without any deleterious effects on carcass traits of steers.

• Journal of Veterinary Clinics
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• v.33 no.5
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• pp.266-269
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• 2016

Cell-free fetal RNA is useful to determine fetal sex and detect other inherent genetic disorders. However, non-invasive fetal sex determination methods using fetal RNA from maternal plasma is not yet well established in studies pertaining to bovine animals. Thus, the aim of this study was to systematically evaluate the presence of the male-specific ZRSR2Y gene transcript in maternal plasma using Reverse Transcriptase-Polymerase Chain Reaction (RT-PCR) assays, and to verify its accuracy, sensitivity, and specificity in determining fetal sex between 30 and 100 days of gestation. Overall accuracy, sensitivity, and specificity of the ZRSR2Y gene transcripts in determining fetal sex were 89.1%, 86.3%, and 100%, respectively. The 30 to 100 days of gestation were further classified into five stages of gestation, and each stage had relatively high accurate, sensitive, and specific results. Overall, these results indicate that the expression of the ZRSR2Y gene can be used for fetal sex determination in bovine animals using circulating cell-free RNA in maternal plasma during early pregnancy.

• Journal of Animal Science and Technology
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• v.63 no.5
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• pp.1064-1075
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• 2021

Recently, a high level of dietary crude protein (CP) has become of interest as a possible practice to improve the carcass quality of beef cattle, and its level has been increasing in the field. However, there is little scientific evidence that supports this. This study was conducted to test whether a high dietary CP level would improve growth performance, body metabolism, and carcass traits in Hanwoo beef cattle. A total of 32 Hanwoo finishing beef cattle (18 multiparous cows, six heifers, and eight steers) participated in a 12-weeks feeding trial. Two kinds of total mixed rations were prepared to contain two different CP; 156 g/kg for the control (CON) and 173 g/kg of CP for the treatment (HCP), while maintaining a similar level of metabolizable energy. The experiment was ended when more than half of the steers reached the target body weight (730 kg). Blood was collected at the end of the experiment. After harvesting, the carcass trait was evaluated at the slaughterhouse according to Korean standards. The carcass yield score and grade were also calculated based on revised criteria. Overall, dry matter intake, average daily gain, blood metabolites concentration, and the carcass traits, except for backfat thickness and the yield score, did not differ between the treatments. The HCP had lower backfat thickness than those of CON. There was no difference in the carcass yield grade, but the yield score was higher in the HCP treatment. According to the newly revised carcass grading criteria, both yield score and grade were higher in HCP than in CON. Increasing CP supply decreased the carcass's backfat thickness without altering growth performance and body metabolism, resulting in improved yield score and grade. Therefore, feeding a high CP diet may be beneficial in the farm income, although it may also increase feed cost and nitrogen excretion to the environment.

• Korean Journal of Agricultural Science
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• v.46 no.3
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• pp.579-589
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• 2019

Due to the ban on the use of antibiotics, interest has been increasing for the development of therapeutic agents to treat various diseases using natural resources. Osthole, a natural coumarin compound used in traditional Chinese medicines, exerts an anti-inflammatory effect, but its effects in cows remain unknown. In this study, the effect of osthole on lipopolysaccharide (LPS)- or concanavalin-A (Con-A)- stimulated peripheral blood mononuclear cells (PBMCs) was assessed. Jugular venous blood was collected from Korean calves, and PBMCs were isolated. They were then used to study the immune response of PBMCs to treatment with osthole and LPS or Con-A for 72 h by measuring inflammatory cytokines including tumor necrosis factor-${\alpha}$ ($TNF-{\alpha}$) and interferon-${\gamma}$ ($IFN-{\gamma}$). Osthole significantly inhibited the mRNA secretion of $TNF-{\alpha}$ and $IFN-{\gamma}$ in a dose-dependent manner. Therefore, osthole inhibited LPS- or Con-A- induced $TNF-{\alpha}$ and Con-A-induced $IFN-{\gamma}$ production significantly in dose-dependent manner. These results clearly suggest that osthole inhibited the LPS- or Con-A- stimulated upregulation of pro-inflammatory cytokines in a dose-dependent manner, without causing obvious cytotoxic effects. Osthole could also protect cows from LPS- or Con-A- induced endotoxin shock, possibly by inhibiting the production of pro-inflammatory cytokines, which suggests that osthole might be a novel therapeutic agent for the prevention of inflammatory diseases.

• Animal Bioscience
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• v.34 no.1
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• pp.85-92
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• 2021

Objective: The objectives of this study were to determine the in situ degradation parameters and appropriate feeding level of pineapple cannery by-products (PCB) based on the growth performance and blood parameters of growing Hanwoo (Bos taurus coreanae) steers fed various levels of PCB. Methods: Two ruminally cannulated Holstein cows were used for in situ disappearance rate measurements. Nylon bags (5×10 cm, 45 ㎛ pore size) filled with 5 g of PCB in triplicate were inserted into the ventral sac of the two cannulated Holsteins cows and incubated for 0, 2, 4, 8, 16, 24, and 48 h. A total of 16 castrated growing Hanwoo steers (12.5±0.5 months old, 302.9±25.7 kg of initial body weight [BW]) were used for the experiment. Animals were stratified by initial BW and then randomly assigned to one of four experimental diets (0%, 1.5%, 3.0%, or 6.0% of PCB, on the dry matter [DM] basis) fed for 91-d, including 30-d of adaptation. Results: Soluble fraction a of DM and crude protein (CP) was 61.9% and 86.0%, fraction b of DM and CP was 32.7% and 11.2%, and indigestible fraction c of DM and CP was 5.4% and 2.8%. The 6.0% PCB feeding group showed lower productivity compared to animals in the other treatments. Increasing the dietary level of PCB did not alter DM intake, but it was numerically lowest in the 6.0% feeding group. The gain to feed ratio was linearly decreased by increasing of PCB. The quadratic broken-line test estimated that 2.5% (DM basis) was the maximum feeding level of PCB in growing Hanwoo steers (y = 0.103 - 0.001×[1.245-x]2, R2 = 0.18). Conclusion: Diets containing up to 2.5% PCB can be fed to growing Hanwoo steers without adverse effects on growth performance.

• Animal Bioscience
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• v.36 no.2
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• pp.238-247
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• 2023

Objective: Recently, indigenous Korean grass Sasa quelpaertensis Nakai (SQ) has garnered much interest as a roughage source for livestock to mitigate its adverse effects on habitat diversity. Thus, the objective of the present study was to evaluate the ruminal fermentation, palatability, and nutrient digestibility of SQ for Korean native beef cattle (Hanwoo) using in vitro rumen fermentation, in situ rumen degradability, and in vivo feeding trials. Methods: Using in vitro tests with rumen fluid as the inoculum for 48 h, ruminal fermentation of SQ was evaluated and compared with that of other roughage sources commonly used in Korea (i.e., rice straw, Timothy hay, and Italian ryegrass [IRG]). Additionally, an in situ trial 96 h was performed using three cannulated Hanwoo steers. Further, an in vivo trial was performed using eight Hanwoo steers to compare the palatability of SQ with rice straw in total mixed ration (TMR) and forage-concentrate separate feeding conditions. Finally, an in vivo digestibility trial of SQ fed as TMR of two particle sizes was performed with four Hanwoo steers. Results: In vitro and in situ trials revealed that SQ was comparable or superior to rice straw in terms of the ruminal fermentation characteristics of pH, gas production, total volatile fatty acid content, and effective ruminal dry matter digestibility (DMD), although its fermentability was lower than that of Timothy hay and IRG. In the palatability test, steers showed a greater preference for SQ when given as TMR. The total tract DMD of SQ fed as TMR was 75.9%±1.37%, and it did not differ by particle size. Conclusion: The feed value of SQ as a roughage source for Hanwoo steers is comparable or superior to that of rice straw, particularly when provided as TMR.

• Korean Journal of Agricultural Science
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• v.49 no.1
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• pp.93-102
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• 2022

This study was conducted to evaluation the effects of dietary soybean meal (SBM) and fermented soybean meal (FSBM) on the growth performance of Korean native cattle as Hanwoo calves (Bos taurus coreanae) and Holstein cows. In total, 16 calves three to four months old (Control group, SBM: 5 males and 3 females, average weight 105.7 kg; Experimental group, FSBM: 5 males and 3 females, average weight 103.7 kg) were fed 5% of the feed amount for 53 days. In terms of growth performance outcomes, the average gain body weight was significantly higher in the FSBM group than in the SBM group in the final fattening period. The average daily gain in body weight (ADGBW) for the FSBM group was higher than that of the SBM group in the final fattening period. The average gain body weight in four months for FSBM was higher than that at three months in the final fattening period. Diarrhea incidence for FSBM was significantly decreased compared to that in the SBM group in the six-week period after weaning. These results indicate that dietary FSBM can improve the growth rate and health condition during the calving period. Holstein cows fed fermented soybean meal had higher milk urea nitrogen levels and decreased somatic cell counts compared to those fed SBM. These results may be closely related with the increased average daily gain body weight associated with dietary FSBM.

• Journal of Veterinary Clinics
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• v.39 no.6
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• pp.342-352
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• 2022

This study was conducted to identify the useful blood variables in diagnosing calf diarrhea in Hanwoo calves and good indicators for calf diarrhea. In 530 Hanwoo calves, fecal scores were recorded on a scale of 0 to 3, and blood samples were collected and analyzed for hematology, serum biochemistry, and acute phase proteins. Among the blood variables, 16 blood variables showed significant differences (p < 0.01) according to fecal scores. After reference intervals of these 16 blood variables were calculated, the distributions of calves by calculated reference intervals showed a significant difference (p < 0.001) and linear associations (p < 0.001) in blood urea nitrogen (BUN), glucose (GLU), blood sodium concentration (Na), blood potassium concentration (K), fibrinogen (Fib), and haptoglobin (Hp). Of 6 blood variables, the optimal cut-off values were calculated for BUN, K, Fib, and Hp, and the area under the curve was 0.5 or more: BUN (9.5 mg/dL, AUC: 0.623), K (5.8 mmol/L, AUC: 0.599), Fib (650.0 mg/dL, AUC: 0.706), and Hp (12.5 mg/dL, AUC: 0.847). These findings could be useful in evaluating calves with diarrhea and making decision of further treatment of calf diarrhea in Hanwoo calves.

• Korean Journal of Agricultural Science
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• v.48 no.4
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• pp.975-985
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• 2021

The sufficient amount of protein supply is crucial for improving the growth performance of growing beef cattle. In addition, due to the improvement in the genetic potential of the carcass weight of Hanwoo steers, dietary protein requirements may be increased during the rapid growth period. Accordingly, the dietary crude protein (CP) level in growing Hanwoo steers has been increasing in the field. However, little scientific evidence is available in relation to this. Therefore, this study was conducted to test whether a higher dietary CP level than convention would improve the growth performance and body metabolism in growing Hanwoo steers. Fifty growing Hanwoo steers were randomly divided into two groups and fed either a commercial diet (CON) or a higher CP (HCP) concentrate mix, provided with a similar level of dietary energy. Tall fescue hay was provided ad libitum. The dietary CP level did not affect growth performance and blood metabolite. Nitrogen intake, predicted nitrogen excretion, and retained nitrogen were higher in the HCP group than in the CON group (p < 0.01). Although there was no difference in the nitrogen utilization efficiency, the growth efficiency per retained nitrogen decreased in the HCP group (p = 0.02). A higher dietary CP level may increase nitrogen retention in growing Hanwoo steers without improving growth performance, which leads to reduced growth efficiency per retained nitrogen. Furthermore, considering the high price of feed protein and increased nitrogen excretion to the environment, a further increase in the protein level may not be sustainable.