• Food Science of Animal Resources
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• v.37 no.5
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• pp.682-689
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• 2017

The aim of this study was to investigate the digestibility of different Korean Hanwoo beef cuts using an in vitro digestion model, in vitro physicochemical upper gastrointestinal system (IPUGS). The four most commonly consumed cuts - tenderloin, sirloin, brisket and flank, and bottom round - were chosen for this study. Beef samples (75 g) were cooked and ingested into IPUGS, which was composed of mouth, esophagus, and stomach, thereby simulating the digestion conditions of humans. Digested samples were collected every 15 min for 4 h of simulation and their pH monitored. Samples were visualized under a scanning electron microscope (SEM) to examine changes in the smoothness of the surface after digestion. Analysis of the amino acid composition and molecular weight (MW) of peptides was performed using reverse-phase high performance liquid chromatography and sodium dodecyl sulfate polyacrylamide gel electrophoresis, respectively. Following proteolysis by the gastric pepsin, beef proteins were digested into peptides. The amount of peptides with higher MW decreased over the course of digestion. SEM results revealed that the surface of the digested samples became visibly smoother. Total indispensable and dispensable amino acids were the highest for the bottom round cut prior to digestion simulation. However, the total amount of indispensable amino acids were maximum for the tenderloin cut after digestion. These results may provide guidelines for the elderly population to choose easily digestible meat cuts and products to improve their nutritional and health status.

• Korean Journal of Agricultural Science
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• v.45 no.3
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• pp.493-498
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• 2018

There has been widespread warming and a general increase in summer temperatures over the Korean peninsula ($0.5^{\circ}C$/10 years from 2001 to 2010). South Korea is transforming into a subtropical region, and the productivity of livestock is affected by the climatic changes. In this study, we investigated whether the summer heat waves affect the developmental competency of Korean native cattle (Hanwoo), a taurine type of cattle with a small portion of indicine varieties. We collected oocytes during the summer (heat stress, HS) and autumn (non-HS condition) and examined the developmental competencies including in vitro maturation and preimplantation embryo development. No significant differences were observed between the HS and non-HS oocytes in nuclear maturation (extrusion of the polar body); however, the cleavage and blastocyst rates were significantly lower in the HS group than those in the non-HS group. The lower developmental competence of the HS oocytes compared to the non-HS is, in part, due to insufficient cytoplasmic maturation because of a higher production of Reactive oxygen species (ROS) levels as well as peri/cortical distributed mitochondria in the HS oocytes after in vitro maturation. Next, we examined the ROS and mitochondria distribution and found a significant increase in the levels of ROS in the HS oocytes and a polarized distribution (pericortical cytoplasm) of mitochondria in the HS oocytes. In summary, impaired cytoplasmic maturation of oocytes from exposure to HS affects the preimplantation embryo development by dysfunction of mitochondria. To improve reproductive performance, embryo transfer using cryopreserved embryos/oocytes is recommended in the hot summer season of South Korea.

• Food Science of Animal Resources
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• v.35 no.3
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• pp.299-306
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• 2015

The objective of this work was to evaluate the growth performance, feed intake, slaughter characteristics, meat quantity and quality characteristics of Hanwoo steers fed with Italian ryegrass (IRG) silage (TRT). IRG silage consisted 11.70% protein, 2.84% ether extract, 53.50% dry matter digestibility and 63.34% total digestible nutrients. The daily weight gain and feed conversion ratio of TRT were significantly (p<0.01) higher than that of control diet (CON; fed rice straw) in the whole periods. However, the slaughter weight, dressing percentage, quantity grade and quantity traits (marbling score, meat color, fat color, and quality grade) of either TRT or CON were similar. Meat fed TRT diet showed higher crude fat and lightness (L*) value and lower moisture content and pH value compared with the CON diet (p<0.05). Overall the carcass yield was 12.5% higher than CON diet.

• Journal of Animal Science and Technology
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• v.48 no.6
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• pp.759-766
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• 2006

This study was conducted to investigate the genetic correlations among the traits used to select young bulls and proven bulls in Hanwoo Performance and Progeny Test Program in Korea. For the estimation of heritabilities and correlations among the growth traits of bulls and carcass traits of progeny steers, 2,532 records of performance tested bull calves and 1,819 records of progeny tested steers were collected from Livestock Improvement Main Center (LIMC), National Agricultural Cooperative Federation (NACF). Fixed effects of mixed model for each traits were selected by using stepwise regression analysis and prior values of variance components were estimated by MTDFREML. The prior values of variance components were estimated with pairwise 2 traits model followed by single trait analysis. The estimated heritability of backfat thickness(BF), dressing percentage(DP), loin-eye muscle area(LMA), marbling score(MS) and weight at 12 months(WT12) was 0.51, 0.32, 0.27, 0.33, 0.50 and 0.26, respectively. Genetic correlation of WT12 of bull calves with backfat thickness, carcass weight and loin-eye muscle area of steers was positive correlation as 0.05, 0.35 and 0.21, respectively. However genetic correlation of WT12 with DP and MS showed negative correlation as 󰠏0.09 and 󰠏0.27, respectively and these negative genetic correlations implies that bulls that may be superior in carcass traits can be lost at the first step of selection and current selection method should be modified to solve this problem.

• Journal of The Korean Society of Grassland and Forage Science
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• v.32 no.2
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• pp.175-184
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• 2012

In the present study, the effects of feeding different forage sources on the growth performance, meat production and meat quality of Hanwoo steers were evaluated using meta-analysis. In total 5 studies that were performed and published in the domestic journals in Korea were employed for the analysis. The results from nutritionally better quality roughage-based steers and rice straw-based steers in each study were assigned as a treatment and a control, respectively, and the mean difference between the treatment and the control was used for the evaluation of effect size. The summary effect was calculated using random effect model. As results, in growth performance, positive effects were found in feed intake, daily weight gain, final body weight and feed efficiency. The significant effect was found only in daily weight gain (p<0.05). In meat production, carcass weight, Longissimus dorsi area, yield index showed positive effect and negative effect was detected in back fat thickness. The significant effect in meat production was found in carcass weight and Longissimus dorsi area (p<0.05). In meat quality, positive effects were represented in marbling score and fat color. Meat color showed little effect. The significance for effects was not observed in the analysis of meat quality. In conclusion, feeding good quality forages to ruminants plays an important role in Korean beef cattle industry and hence further researches are necessary to improve the efficiency of forage utilization in Hanwoo cattle.

• Food Science of Animal Resources
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• v.31 no.1
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• pp.107-114
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• 2011

This study was conducted to investigate the effect of feeding whole crop barley silage (WBS) on the growth performance, carcass grade, and beef quality of Hanwoo steers. Twelve Hanwoo steers (12-mon-old) were allocated into either a control (rice straw fed) or WBS (whole crop barley silage fed) group (six animals per group) and fed for 540 d until the animals reached 30-mon-old. Concentrates and roughage were fed according to the feeding stage phases; finisher I (12.16-monold), II (17.21-mon-old), and III (22.30-mon-old). A significant increase in growth was observed during the finisher I stage for the steer fed WBS, whereas a significant increase in growth occurred during the finisher II stage in the control group. The yield grade of the WBS group increased significantly with a 15.6% increase in the longissimus dorsi area and a 25.7% reduction in back fat thickness. Marbling scores improved 52.4% in the WBS group compared with the control group. A significant difference in treatments was observed for the proximate chemical composition of the crude fat content. The results regarding palatability traits in the WBS group showed a significant improvement in appearance. The results indicate that the WBS group had improved longissimus muscle and marbling scores on carcass grading compared to the control.

• Journal of Animal Science and Technology
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• v.50 no.3
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• pp.363-372
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• 2008

To investigate the effects of total mixed ration(TMR) on growth performance and carcass characteristics of Hanwoo steers, sixty steers were randomly assigned to one of four treatment groups; separate feeding of concentrate and rice straw(control), wet TMR(TMRⅠ), dry TMR with 20%(TMRⅡ) and 40%(TMRⅢ) barley bran from 6 to 28 month of age. In growth performance, average daily gains of TMRⅡ group was the highest(0.70kg/day) but significant differences between treatments were not found(p>0.05). Average feed required for kg body weight gain of control group was 11.63kg. Those of TMRⅠ through TMRⅢ were 9.29, 10.46 and 10.71kg, respectively. Dressing percentage and retailed cut percentage were 59% and 63%, without any significant differences between treatments(p>0.05). There were no significant differences in rib-eye area, back fat thickness, meat color and fat color (p>0.05). Average marbling score was higher(p<0.05) in TMRⅠ than in control group.

• Korean Journal of Animal Reproduction
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• v.26 no.3
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• pp.291-298
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• 2002

This study was carried out to investigate the reproductive status and the effect of progesterone treatment on the recovery of reproductive disorders in Hanwoo. Hanwoo farms were surveyed the general management status, such as the type of barn, the feed intake, the incidence of reproductive disorders. The reproductive disorder cattle were treated 7 days insertion of control internal drug releasing for cattle (CIDR) and injection of PGF$_2$$\alpha$ at 1 day before removal. The recovery of reproductive disorders was assessed by determining the pregnancy following artificial insemination. The total number of surveyed Hanwoo farms was 127, and the total incidence rate of reproductive disorders was 19.7% (209/1,061). Compared to the herd size, the incidence rates of reproductive disorders in less than 10 heads (37.5%) was significantly (P<0.05) higher than in 10 to 20 heads (14.7%) and more than 20 heads (13.6%) of herd size per farm. The incidence rate of reproductive disorders in tie stall barn was significantly (P<0.05) higher than in free stall barn (30.4% vs. 14.7%), and even in free stall barn, that tended to decrease as the floor area was larger. The incidence rate of reproductive disorder by the parity was highest in heifer (50.7%), and that tended to decrease as the parity was increased. The distribution rate of the case of reproductive disorder in anestrus, recovery rate of reproductive disorders fellowing CIDR treatment was 75.1% (157/209). In the recovery rate of reproductive disorders by body condition score (BCS), BCS 1, 2 and 3 was significantly (P<0.05) higher pregnancy rate (85.7, 84.9 and 86.8%), and gross recovery rate in emaciated cattle was better than in obese cattle (BCS 4, 5). In conclusion, the incidence rate of reproductive disorders in Hanwoo raised in Youngju province area was 19.7%, and that tended to decrease as the herd size was increase because of increased farmer's attentions, and the floor area was larger. The majority of the case of reproductive disorders was anestrus. The recovery rate of reproductive disorders following CIDR treatment was 75.1%, and to optimize the recovery rate of reproductive disorders, cows and heifers were maintained BCS 1, 2 and 3 by moderate management.

• Journal of Animal Science and Technology
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• v.51 no.3
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• pp.241-248
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• 2009

Metabolic trial with 3 fistulated sheep was conducted in a 3 $\times$ 3 Latin square design and feeding trial with 24 Hanwoo steers in 12 month of age for 20 months was conducted to investigate the replacing effect of rice straw with fermented spent mushroom (Flammuliua velutipes) compost (FSMC) on fermentation characteristics, ruminal effective degradabilty and whole tract digestibility of nutrients in sheep, and to examine the growth performance of Hanwoo steers. Experimental diets for the metabolic trial with sheep were commercial concentrates and rice straw in the ratio of 70 : 30 (CON, DM basis). Same concentrate with 30% FSMC and 70% rice straw (FSMC-30) and 60% FSMC and 40% rice straw(FSMC-60). Diets for Hanwoo steers in three treatments were same as for metabolic trial in replacing ratio of rice straw with FSMC. pH of rumen fluid in sheep was not affected by FSMC. Ammonia-N content in the rumen fluid was highest in the sheep fed FSMC-60 at 3h (P<0.045). The CON diet increased (P<0.001) acetate proportion at 1h and 3h post feeding compared to FSMC-60 diet while propionate proportion was highest in the sheep fed FSMC-60 diet for all the sampling times (P<0.027~P<0.002). Increased proportion of butyrate was observed at 30 min prior to feeding (P<0.031), and 1h (P<0.011) and 6h(P<0.039) post feeding from sheep fed FSMC-30 diet compared to those from sheep fed other diets. Effective degradability in the rumen was not influenced by experimental diets. Whole tract digestibility of crude protein (P<0.031) and neutral detergent fiber (P<0.006) tended to be increased in the sheep fed CON diet while corresponding values were lowest in the sheep fed FSMC-60 diet. Total body weight gain of Hanwoo steers for 8 months was not different among diets, thus daily body gain was not influenced by the experimental diets.

• Journal of Animal Science and Technology
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• v.49 no.6
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• pp.801-818
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• 2007

This study was carried out to determine the effects of processing methods of barley as a proper source of grain in diets of Hanwoo on fermentation pattern in the rumen fluid and digestibility of the diets, the growth performance and carcass characteristics of Hanwoo. The degree of ruminal pH change in the cows fed diets of the Corn(corn basis) and GDRB(ground and dry-rolled barley) tended to be greater than those in the cows fed other two diets (ground barley, GB and dry-rolled barley, DRB). The diet of GDRB showed the lowest ruminal pH(5.5), indicating the rapid degradation of the diet in the rumen. Although ammonia concentration was not affected by diet, the GR and DBR diets maintained the low concentrations of ruminal ammonia compared with other two treatments. And the effects of feeding processed barley grain on body weight gain and meat quality of Hanwoo steers were as follows. Steers fed DRB diet had the highest body weight, 683.0kg at 28 months old, while those fed the GDRB showed the lowest body weight, 653.3kg. The average daily gain(ADG) was similar between the steers fed Corn and GR throughout the whole period, but the GDRB showed the lowest ADG. The steers fed the DRB showed the significant increase in ADG(0.89kg/d from 19 to 23 months old and 0.43kg/d from 24 to 28 months old) compared with those fed other diets. Feeding diets containing corn and/or barley did not influence live body weight, cold carcass weight, carcass yield, back-fat thickness and carcass grade of Hanwoo steers.