• Journal of Animal Science and Technology
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• v.66 no.3
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• pp.614-629
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• 2024

Hanwoo beef is in high demand because of its unique flavor, freshness, and high-fat content. However, the longer rearing period required to enhance marbling in Hanwoo cattle has adverse environmental consequences, such as greenhouse gas emissions and overall rearing costs. To address consumer preferences for leaner and healthier meat, the Korean meat industry has recently introduced Hanwoo heifer meat as an alternative source, but its quality traits are still unclear. Nevertheless, there is a limited body of research exploring the impact of Hanwoo gender (steer, heifer, and cow) and their corresponding slaughter ages on meat quality traits. This study looked into how gender affected the physicochemical and qualitative features of Hanwoo striploin at their respective slaughter ages. Results revealed that cow striploin has higher levels of moisture (66.81%) and protein (20.76%), whereas it contains lower levels of fat (10.66%) and cholesterol (34.66 mg/100 g). Regarding the physicochemical properties, cow striploin exhibited significantly lower shear force, color indexes, and soluble collagen (p < 0.05). However, chondroitin (1.19%) and muscle fiber area (1,545.23 ㎛²) were significantly higher in steer striploin than in heifer and cow (p < 0.05). Cow striploin exhibited significantly higher levels of oleic acid, unsaturated fatty acids (UFAs), and monounsaturated fatty acids (MUFAs) while having lower levels of eicosadienoic acid and atherogenic index compared to the other two groups. Cows and heifers had higher concentrations of amino acid metabolites than striploin from steers. Furthermore, bioactive metabolites such as carnitine and carnosine content were found higher in cow and heifer respectively. Overall, Hanwoo cattle gender influences the qualitative attributes of striploin; nevertheless, compared to steer and heifer striploin, cow striploin is a relatively good source of protein, fatty acid content, and metabolites conducive to a healthy diet.

• Food Science of Animal Resources
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• v.20 no.2
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• pp.87-92
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• 2000

This study was performed to provide scientific information for consumers and to increase the quality and consumption of Sullungtang prepared with bone from Hanwoo. The physico-chemical, sensory, nutritional properties of Sullungtang by different parity were investigated. The extracting extents of blood were significantly higher for heifer among Hanwoo cows with different parity(none, the second or the fourth) and for back bones among different bone portions (round, hind shank, arm, fore shank or back bone) (p〈0.05). For Sullungtang extracted from bones of heifer was higher in collagen contents than those extracted from cows with the second or the fourth parity. Sullungtang extracted from bones of heifer and cows with the second parity had significantly higher contents of condroitin and viscosity than those of cows with the fourth parity, however there was no significant difference between heifer and cows with the second parity. In color, L values were significantly high, and a and b values were significantly low for Sullungtang extracted from bones of heifer when compared to those extracted from the other cows with the second parity. The contents of total nitrogen, sodium, or calcium were higher for Sullungtang extracted from heifer than those from the cows with the second or the fourth parity. In amino acid compositions, the percentages of glycine were highest and proline and glutamic acid were followed fro all Sullungtang samples from Hanwoo. The results showed that the overall quality of Sullungtang significantly decreased as the parity increased for Hanwoo cows. The Sullungtang extracted from bones of heifer had the best sensory scores as well as nutritional quality when compared to those extracted from the cows with parity. Therefore, the labeling and price for cow bones should be differently evaluated by their parity and age in marketing system.

• Reproductive and Developmental Biology
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• v.37 no.2
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• pp.75-77
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• 2013

This study was conducted to investigate optimal time of artificial insemination (AI) to Hanwoo female after natural estrus. AI was occurred 12 and 24 hours after natural estrus in both heifer and multiparous recipient then pregnancy and parturition rates were estimated. Results indicated that AI performed at 24 hours after natural estrus showed significant (p<0.05) higher pregnancy rate in both heifer and multiparous recipient groups with significantly (p<0.05) higher abortion rate. However, there are no significant differences of parturition rate, twin birth and sex ratio in both heifer and multiparous recipient groups. Therefore, our results may suggest that performance of AI at 24 hours after natural estrus promise higher pregnancy rate than AI at 12 hours after natural estrus in both heifer and multiparous recipient.

• Korean Journal of Organic Agriculture
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• v.24 no.4
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• pp.931-944
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• 2016

This study was conducted to compare among bull, steer and heifer on growth performance, blood composition and carcass traits according to fattening phase in Hanwoo. 12 month of aged 4 bulls ($339.8{\pm}18.5kg$), 4 steers ($309.8{\pm}13.2kg$), and 3 heifers ($290.0{\pm}16.7kg$) were allocated in the stalls with individual feeding system during 20 months. Average daily gain was not different among the treatment groups during early fattening phase, but higher in the bulls and lower in the heifers after mid-fattening phase (p<0.05). The difference of body size by animal groups appeared from 24 month of age, and wither height and body length of Hanwoo heifer were the smallest (p<0.05) among treatment group. But wither height was not difference among treatment groups at 32 month of age. At 12 month of age, concentrations of serum cholesterol, triglyceride, glucose and total protein were higher in the heifers compared to other groups, and serum GPT (Glutamic pyruvic transaminase) was the highest (p<0.05) in the bulls, and serum GOT (Glutamic oxaloacetic transaminase) was the highest (p<0.05) at late fattening phase in the bulls. Meat yield index was similar between the bulls and the heifers, and the lowest (p<0.05) in the steers. Marbling score was significantly higher (p<0.05) in the steers and the heifers than in the bulls, and meat quality was the best in the steers among treatment groups. The results of this experiment might be used as a basal data on difference between gender in revision of Korean feeding standard for Hanwoo.

• Korean Journal of Agricultural Science
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• v.46 no.1
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• pp.27-31
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• 2019

It is well documented that intensive selection in dairy cattle for economic value such as increased milk yield led to a decline in reproductive performance. Recent studies using genome-wide association studies (GWASs) discovered candidate genes involved in the lower fertility including embryo development and conception rates. However, the information, which showed a lower reproductive performance, is limited to dairy cattle, especially Holstein, and the candidate genes were not examined in the Korean native cattle Hanwoo which has been intensively selected and bred for meat in the last few decades. We selected the candidate genes WBP1 and PARM1 reported to be associated with cow and/or heifer conception in dairy cattle and analyzed the genotype because those genes have non-synonymous single nucleotide polymorphisms (SNPs). To determine the single base change, we used the high resolution melting (HRM) assay which is rapid and cost-effective for a small number of genes. We found that most heifers with higher conception (1: service per conception) have the AA genotype coding Threonine rather than Proline in the WBP1 gene. We did not detect an association for a SNP in PARM1 in our analysis. In conclusion, the genetic variation of WBP1 can be used as a selective marker gene to improve reproductive performance, and HRM assay can be used to identify common SNP genotypes rapidly and cost effectively.

• Journal of Embryo Transfer
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• v.23 no.4
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• pp.257-261
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• 2008

The objective of present study was to investigate the effect of seasons on reproductive performance of Hanwoo and Holstein heifers. Heat stress in summer or cold stress in winter stress to Hanwoo and Holstein heifers may bring reproduction failure, which would pose an important economic loss, even around Daegwallyeong region located in high mountainous area. Seasonal differences in the serum levels of LH, FSH and progesterone ($P_4$) in response to environmental factors (hot and cold) out of 20 pubertal Hanwoo heifers in Daegwallyeong, Gangwon Province and 20 non-lactating Holstein heifers in Chonan city of Republic of Korea at 2-3 years of age were compared. Blood samples for hormonal analysis were from jugular vein after detection of estrus repeatedly over four seasons within four-week intervals (Spring: May to June, Summer: July to August, Autumn: October to November and Winter: January to February). In Hanwoo heifer population, averages of LH and FSH concentration in spring and in summer were greater compared to those in winter (p<0.05). LH or FSH levels tended to be greater (p=0.06) in spring and less (p=0.09) in winter compared to the levels in autumn. Only in summer, cattle seemed to show lower LH or FSH secretion (p<0.05). Similar to the results in Hanwoo heifers, the serum concentrations of LH and FSH in Holstein heifers decreased further by heat stress in summer when P 4 levels were high during luteal phase. The results demonstrate significant effect of summer heat on reproduction of Hanwoo or Holstein heifers. Although parameters indicating the extent of heat stress were not measured in this study, we suggest that serum hormone levels could be considered as successful indicators of summer heat stress condition for Hanwoo and Holstein heifers even under rather cool summer climate.

• Journal of Embryo Transfer
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• v.31 no.3
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• pp.261-265
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• 2016

The aim of the present study was to evaluate and estimate timing of artificial insemination (AI) in Hanwoo heifer (Korean native cattle) that is the most popular breed of beef cattle in Korea. To determine changes in body weight of heifers around AI, body weight were measured at different stages either before or after AI. We found that daily body weight gain was higher in the pregnant cows after AI. We also investigate correlation between body mass measured by shoulder height and body length, and conception rates, used (body length+ height)2 instead of height2 for body mass index (BMI), and found that relatively more BMI heifers (>55) showed higher conception rates. Finally, we estimated body weight by measuring should height (SH), heart girth (HG), and body length (BL); $BW=3.93372^*HG-2.90985^*SH-0.021^*BL$. In addition, we observed that HG is most closely correlated with BW; $y(BW)=1.77355^*x(HG)$, $R^2=0.98881$. In summary, we can determine the best timing of AI using body measurement and its application including BMI.

• Journal of Animal Science and Technology
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• v.57 no.1
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• pp.3.1-3.6
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• 2015

This study investigated the effects of feeding by-product feed (BF)-based silage on the behavior of growing Hanwoo heifers. Twelve Hanwoo heifers (13.2 months-old, 315 kg body weight; four heifers per pen) were assigned to three diets: a rice straw (RS) diet (concentrate mix and free access to RS), a RS and BF-based silage (RSBFS) diet (concentrate mix and free access to RS and BF-based silage), and a BF-based silage (BFS) diet (concentrate mix and free access to BF-based silage). Behavior was recorded for 5 days using camcorders. Compared to the RS group, the BFS group showed 21.7% higher dry matter intake, shorter feeding, rumination, and chewing times, as well as longer resting time (p < 0.05). Although all groups exhibited similar drinking, urination, and defecation frequencies, the BFS group exhibited higher feeding rates, rumination efficiency, and chewing efficiency than the RS group (p < 0.05). Compared to the BFS group, the RSBFS group showed higher $peNDF_{8.0}$ intake (15.2% vs. 25.0% dry matter intake), longer feeding and sitting times, lower defecation frequency (p < 0.05), and similar rumination efficiency. In conclusion, complete replacement of conventional RS with BF-based silage reduced rumination and chewing activity in growing Hanwoo heifers, and BF-based silage feeding with large-particle straw is an effective approach in improving heifer behavior.

• Journal of The Korean Society of Grassland and Forage Science
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• v.35 no.3
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• pp.232-237
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• 2015

The present study investigated the effects of Lysophospholipid (LPLs, LIPIDOL$^{TM}$) on the growth performance and nutrient digestibility of Hanwoo heifers. A feeding trial was performed for 120 days until slaughter using a herd of 24 Hanwoo heifers. Eight heifers were assigned to each of 3 experimental groups (control, 0.3% LIPIDOL$^{TM}$ and 0.5% LIPIDOL$^{TM}$). Growth performance, nutrient digestibility, and carcass characteristics were investigated. Significantly improved nutrient digestibility was found in the LIPIDOL$^{TM}$ treatment group compared to the control (p<0.05). No significant effect by LIPIDOL$^{TM}$ supplementation on growth performance was observed (p>0.05). However, interestingly, greater carcass weight was detected in the treatment of LIPIDOL$^{TM}$ where less daily gain was found. Although not a significant effect, greatly decreased back-fat thickness and increased loin area were detected in the treatment of LIPIDOL$^{TM}$. In meat characteristics, LIPIDOL$^{TM}$ increased intramuscular fat and tenderness. Therefore, the present study results suggest that the inclusion of LIPIDOL$^{TM}$ in the diet of Hanwoo heifers can improve carcass performance and meat quality by increasing the carcass index and the meat quality index. The results also suggest that a level of 0.3% might be more efficient than 0.5% with regard to economic effectiveness.

• Journal of Embryo Transfer
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• v.29 no.4
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• pp.327-331
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• 2014

The objective of this study was to investigate the interrelationship of weight and hormonal changes through the administration of vitamin A to first time pregnant heifers. A total of 28 Korean heifers was used for this study. The heifers were divided into two groups - with vitamin A (n=14) and without vitamin A (control) (n=14) in the feed. Body weight increased in vitamin A treated heifers starting 9 months until 15 months. After pregnancy, vitamin A treated heifers were found to maintain higher body weights than the control group. Pre-pregnancy and post pregnancy progesterone levels were not different between the two groups. Serum estradiol levels of heifers at different growth stages showed relatively higher E2 levels than the control. Also, the control during pregnancy may show higher serum E2 levels than the vitamin A treated heifers. The growth phase serum estradiol levels in heifers may be relatively higher than the control. During pregnancy it showed a similar trend. Serum levels of vitamin A treated heifers did not differ from pregnant heifers at 5 months of age. However, after 5 months from conception until 8 months of treatment it showed a high level. Serum cholesterol in pregnant cows was higher in the control group than the treatment from beginning until the end of pregnancy. This is considered to be related to fetus development during pregnancy, as well as the mother's health.