• Asian-Australasian Journal of Animal Sciences
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• v.30 no.8
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• pp.1117-1123
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• 2017

Objective: This study was conducted to compare growth performance, blood components and carcass traits by two feeding systems (concentrate with roughage separately [CON] vs total mixed ration [TMR]) in Hanwoo steers, and to learn the relationship between blood components during fattening or finishing phases and carcass traits in Hanwoo steers. Methods: Sixty steers aged 8 months were allotted to two feeding systems and fed similar amounts of average dry matter and total digestible nutrient throughout whole experimental period according to each feeding program. Steers were weighed monthly, taken blood at the end of growing, fattening and finishing periods, and slaughtered at 30 month of age. Results: Growing performance was higher (p<0.05) in the CON group compared to the TMR group during fattening and finishing periods. The CON group was lower (p<0.05) in blood aspartic acid transaminase, blood urea nitrogen and retinol levels during growing period, but higher in triglyceride and cholesterol levels during fattening and finishing periods compared to the TMR group. The CON group was greater (p<0.05) in rib-eye area, and lighter (p<0.05) red in meat color compared to the TMR group. In the correlation coefficients between blood components of steers and carcass traits, retinol had a negative (p<0.05) correlation with marbling score and rib-eye area. Leptin had a positive (p<0.05) correlation with back fat thickness. Blood cholesterol and triglyceride were positively (p<0.05) correlated with carcass weight and rib-eye area. Conclusion: Growth performance, carcass ribeye area and meat color showed a more desirable result in the CON compared to the TMR in Hanwoo steers. Assessing the accumulated data of carcass traits with blood components including hormones-particularly retinol, cholesterol, triglyceride, and leptin-during the fattening or finishing phases, it may be possible to find a biomarker for determining beef quality in living animals.

• Asian-Australasian Journal of Animal Sciences
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• v.28 no.2
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• pp.180-187
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• 2015

This study was conducted to determine the effects of feeding by-product feed (BF)-based silage on the performance, blood metabolite parameters, and carcass characteristics of Hanwoo steers. The BF-based silage was composed of 50% spent mushroom substrate, 21% recycled poultry bedding, 15% cut ryegrass straw, 10.8% rice bran, 2% molasses, 0.6% bentonite, and 0.6% microbial additive (on a wet basis), and ensiled for over 5 d. Fifteen steers were allocated to three diets during the growing and fattening periods (3.1 and 9.8 months, respectively): a control diet (concentrate mix and free access to rice straw), a 50% BF-based silage diet (control diet+50% of maximum BF-based silage intake), and a 100% BF-based silage diet (the same amount of concentrate mix and ad libitum BF-based silage). The BF-based silage was fed during the growing and fattening periods, and was replaced with larger particles of rice straw during the finishing period. After 19.6 months of the whole period all the steers were slaughtered. Compared with feeding rice straw, feeding BF-based silage tended (p = 0.10) to increase the average daily gain (27%) and feed efficiency (18%) of the growing steers, caused by increased voluntary feed intake. Feeding BF-based silage had little effect on serum constituents, electrolytes, enzymes, or the blood cell profiles of fattening steers, except for low serum Ca and high blood urea concentrations (p<0.05). Feeding BF-based silage did not affect cold carcass weight, yield traits such as back fat thickness, longissimus muscle area, yield index or yield grade, or quality traits such as meat color, fat color, texture, maturity, marbling score, or quality grade. However, it improved good quality grade (1+ and 1++) appearance rates (60% for the control group vs 100% for the BF-based silage-fed groups). In conclusion, cheap BF-based silage could be successfully used as a good quality roughage source for beef cattle.

• Asian-Australasian Journal of Animal Sciences
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• v.23 no.4
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• pp.417-424
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• 2010

The purpose of this study was to detect significant SNPs for carcass quality traits using DNA chips of high SNP density in Hanwoo populations. Carcass data of two hundred and eighty nine steers sired by 30 Korean proven sires were collected from two regions; the Hanwoo Improvement Center of National Agricultural Cooperative Federation in Seosan, Chungnam province and the commercial farms in Gyeongbuk province. The steers in Seosan were born between spring and fall of 2006 and those in Gyeonbuk between falls of 2004 and 2005. The former steers were slaughtered at approximately 24 months, while the latter steers were fed six months longer before slaughter. Among the 55,074 SNPs in the Illumina bovine 50K chip, a total of 32,756 available SNPs were selected for whole genome association study. After adjusting for the effects of sire, region and slaughter age, phenotypes were regressed on each SNP using a simple linear regression model. For the significance threshold, 0.1% point-wise p value from F distribution was used for each SNP test. Among the significant SNPs for a trait, the best set of SNP markers were selected using a stepwise regression procedure, and inclusion and exclusion of each SNP out of the model was determined at the p<0.001 level. A total of 118 SNPs were detected; 15, 20, 22, 28, 20, and 13 SNPs for final weight before slaughter, carcass weight, backfat thickness, weight index, longissimus dorsi muscle area, and marbling score, respectively. Among the significant SNPs, the best set of 44 SNPs was determined by stepwise regression procedures with 7, 9, 6, 9, 7, and 6 SNPs for the respective traits. Each set of SNPs per trait explained 20-40% of phenotypic variance. The number of detected SNPs per trait was not great in whole genome association tests, suggesting additional phenotype and genotype data are required to get more power to detect the trait-related SNPs with high accuracy for estimation of the SNP effect. These SNP markers could be applied to commercial Hanwoo populations via marker-assisted selection to verify the SNP effects and to improve genetic potentials in successive generations of the Hanwoo populations.

• Journal of Animal Science and Technology
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• v.47 no.3
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• pp.447-456
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• 2005

This study was conducted to evaluate the effects of energy level of concentrate feed in finishing Hanwoo steers for 6 months before slaughter. Feeding trial was done with 2 treatment groups, IDN72 (72% of TDN in concentrate) and TDN74 (74 % of TDN in concentrate). The body weight (from 19 to 24 months) tended to be higher in TDN74 than in TDN72, but was not significant. Average daily gain of TDN74 was higher by 4.4 % in comparison to TDN72. There was no significant differences in concentrate, dry matter and TDN intake per I kg body weight gain between TDN72 and TDN74. And there was a tendency to improve crude protein intake per I kg body weight gain by increasing TDN content from 72 to 74 %. The dressing percentage tended to be higher in TDN74 than in TDN72, but was not significant. Salable meat percentage tended to be lower in TDN74 than in TDN72 because of higher body fat percentage in TDN74 than in TDN72. There were no significant differences in marbling score, meat color, fat color, carcass weight, rib-eye area and back fat thickness between TDN72 and TDN74. Significant differences were not found in shear value, cooking loss, water holding capacity or moisture and protein contents of longissimus dorsi (LD) muscles between TDN72 and TDN74. Fat content of LD muscles tend to be lower in TDN74 than in IDN72 but without any significance. There was a tendency to improve juiciness and taste by feeding IDN74 rather than TDN72. Especially, tenderness of TDN74 was increased by 7.4% in comparison to TDN72 (p < 0.05). Gross income from TDN74 was higher than TDN72 by 5% The results suggested that significant differences were not found in growth performance, feed conversion and carcass characteristics between TDN72 and TDN74. The results also show that more studies are required to clarify the energy level for finishing Hanwoo steers.

• Journal of Animal Science and Technology
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• v.51 no.3
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• pp.225-230
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• 2009

This experiment was carried out to investigate the effects of ruminally inserted artificial fiber (RIAF; polymerized fibrous implements) on growth performance, feed intake and carcass characteristics of Hanwoo steers. Thirty six steers averaging $368.3\pm20.3kg$ were randomly assigned into three groups: control group, the ruminal insertion of three pieces (T1), and five pieces (T2) of RIAF. Average daily gain, feed intakes and conversions among treatments were similar. Numbers of rumen villi were higher in RIAF treatment (T1 and T2) groups than control group, but they were not significant (p>0.05). The length of villi were significantly longer in T2 than control group (p<0.05). Fecal weight tended to decrease in T1 compared with the control group (p>0.05). There was no differences on carcass traits inc1uding longissmus muscle area, back fat thickness, marbling score, meat color, and fat color among treatments.

• Journal of Animal Science and Technology
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• v.62 no.4
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• pp.429-437
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• 2020

This study was conducted to construct basic data for the selection of elite cows by analyzing the estimated breeding value (EBV) and accuracy using the pedigree of Hanwoo cows in Gyeongnam. The phenotype trait used in the analysis are the carcass weight (CWT), eye muscle area (EMA), backfat thickness (BFT) and marbling score (MS). The pedigree of the test group and reference group was collected to build a pedigree structure and a numeric relationship matrix (NRM). The EBV, genetic parameters and accuracy were estimated by applying NRM to the best linear unbiased prediction (BLUP) multiple-trait animal model of the BLUPF90 program. Looking at the pedigree structure of the test group, there were a total of 2,371 cows born between 2003 to 2009, of these 603 cows had basic registration (25%), 562 cows had pedigree registration (24%) and 1,206 cows had advanced registration (51%). The proportion of pedigree registered cows was relatively low but it gradually increased and reached a point of 20,847 cows (68%) between 2010 to 2017. Looking at the change in the EBV, the CWT improved from 4.992 kg to 9.885 kg, the EMA from 0.970 ㎠ to 2.466 ㎠, the BFT from -0.186 mm to -0.357 mm, and the MS from 0.328 to 0.559 points. As a result of genetic parameter estimation, the heritability of CWT, EMA, BFT, and MS were 0.587, 0.416, 0.476, and 0.571, respectively, and the accuracy of those were estimated to be 0.559, 0.551, 0.554, and 0.558, respectively. Selection of superior genetic breed and efficient improvement could be possible if cow ability verification is implemented by using the accurate pedigree of each individual in the farms.

• Journal of Animal Environmental Science
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• v.14 no.2
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• pp.81-90
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• 2008

This study was carried out to investigate the effects of the organic feed on weight gain, feed conversion rate, and carcass characteristics of Hanwoo steers. Three feeding treatments(T1 : rice straw and commercial concentrates, T2 : organic hay and concentrates, T3 : organic corn silage and concentrates) for 22 months (from 6 to 28 months) were used. As a result, weight gain was not significantly different among treatments throughout this study. Also T1 tended to improve weight gain and daily weight gain without significance. The percentage of meat quality grade over the first grads ($1,\;1^+,\;1^{++}$) were 50% in the carcass of Hanwoo steers fed T1 and T2, and 70% fed T3, respectively. T2 and T3 tended to improve marbling score and oleic acid content.

• 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.

• Asian-Australasian Journal of Animal Sciences
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• v.23 no.7
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• pp.952-959
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• 2010

This study was conducted to evaluate growth, behavior and carcass traits of fattening Hanwoo (Korean native cattle) steers managed in different group sizes. A total of 48 animals, 6 months of age, were allocated to one of three group sizes and the experiment was conducted from 12 to 30 months of age. Groups were balanced for weight and the group sizes consisted of 4, 8, or 12 steers which were named 4sG, 8sG and 12sG, respectively. When animals were 12 months of age, initial fasted body weight (BW, $304.51{\pm}12.40\;kg$) was measured. All animals were housed at a constant space allowance of $8.82\;m^2$ per animal, and a feeder and drinker were provided per 4 animals. The whole fattening stage was divided into three phases: phase I (from 12 to 18 month of age), phase II (from 19 to 24 month of age), and phase III (from 25 to 30 month of age). Steers managed in 12sG showed low (p<0.05) growth rate and feed conversion rate (FCR) in phase I and phase II when compared to other treatment groups. However, this difference was not observed for the whole fattening phase (p>0.05). Steers managed in 4sG had a thick (p<0.05) ultrasound back fat thickness at 15 and 18 months of age. However, group size had no effect on meat yield and quality traits of area and marbling score. Animals managed in 8sG yielded a better meat grade of "A" than the "B" grade in other treatment group sizes. Lean color, fat color, firmness and maturity scores did not differ among group sizes. Hanwoo steers housed under 12sG spent less time on eating concentrate, relevant higher eating rate, less frequency of allogrooming, and more time on walking (p<0.05). It could be concluded that a large group size retarded growth rate and back fat thickness in the fattening stage, which was mainly focused on 15 and 18 months of age.

• 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.