• Korean Journal of Poultry Science
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• v.12 no.2
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• pp.113-118
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• 1985

This study was conducted to determine the carcass rates, partcarcass production percentages, nutrient contents and optimum prices of broilers and old layers as related to the body weight. Total 240 birds were used and results obtained are summarized as follows. 1.The carcass rates were 61.41% in young chickens (0.6-0.8kg), 65.07% in semi-bros(1.2-1.4kg) and 66.39% in high- bros (1.7-2.1kg), showing a trend of increased carcass rate as the body weight increased. The carcass rates of old layers were lower than those of broilers, being 62.68% in white old lavers (1.8-2.0kg) and 63.07% in colored old layers (2.1- 2.4 kg) 2. Although there was little difference in part-carcass production percentages between breeds or body weights of broilers, most of the part-carcass was produced from legs, breast, back, wings and neck in order. 3. As the body weight increased, the moisture content of deboned carcass of broilers decreased (71.27% in young chickens, 62.66% in semi-bros and 60.39% in high-bros), while the fat content increased (11.47% in young chickens, 17.60% in semi-bros and 19.87% in high-bros). The protein content of semi-bros (17.21%) was higher than that of young chickens (14.75%) or high-bros (16.93%), but no difference was noted in old layers whether they were white or colored. 4. When compared on the basis of protein or Protein plus fat content in grams per kilogram body weight, the market price of semi-bros per kilogram body weight was more expensive and that of old layers was cheaper than that of high- bros.

• Journal of Animal Science and Technology
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• v.47 no.6
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• pp.1095-1100
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• 2005

For the establishment of prediction strategies of carcass meat quality grade and for the enhancement of prediction accuracy, sixty six Hanwoo steers were ultrasonically tested at 24 months of age. Ultrasonic meat quality grade were predicted by standard ultrasonic image and decision tree method using ultrasonic meat quality index. From the results of decision tree method using ultrasonic meat quality index, it was found that the marbling score was mainly influenced by the distinctness of rib on ultrasound image. Prediction accuracy of meat quality grade by ultrasonic meat quality index was 86.4%, resulting in 7.6% higher accuracy than that by standard ultrasonic image (78.8%).

• Journal of Animal Science and Technology
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• v.45 no.2
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• pp.327-334
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• 2003

This study was carried out to make early prediction of carcass yield grade. Sixty six Hanwoo steers were measured for back fat thickness, longissimus muscle area and body weight at 18, 21 and 24 months of age by ultrasound. Carcass evaluation was done after ultrasound measurement at 24 month of age. Ultrasonic yield grade at 18, 21 and 24 month of age were predicted by regression and decision tree methods. Classifying by carcass yield grade, ultrasonic back fat thickness at 18, 21 and 24 months of age was significantly different in each carcass yield grade (p<0.05). The prediction accuracy of carcass yield grade by regression method was 78.8% at 18 months, 86.4% at 21 months and 90.9% at 24 months of age. By using the decision tree method for carcass yield grade, 78.8%, 89.4% and 89.4% of prediction accuracy were obtained at 18, 21 and 24 months of age, respectively.

• Korean Journal of Food Science and Technology
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• v.37 no.1
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• pp.38-43
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• 2005

Effects of fermented food waste feeds on meat quality and physico-chemical characteristics of fully grown pigs were investigated. Two treatments were tried in this study; commercial feed (control) and fermented food waste feed(FFWF). Except for much thicker backfat of control, carcass traits, carcass weight, dressing percentage, carcass grade, cooking loss, shear force, water-holding capacity, drip loss, NPPC meat color, and marbling score of commercial feed(control)- and fermented food waste feed (FFWF)-fed pigs were not significantly different. Primal cut weights and meat percentages were significantly different (p<0.05) between control and FFWF. pH of FFWF loin was significantly lower (p<0.05) than that of control. FFWF loin showed higher L*-value and lower a*-value compared to control.

• Journal of Animal Science and Technology
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• v.46 no.5
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• pp.719-728
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• 2004

The aims of this study were to estimate genetic parameters for carcass traits on Hanwoo(Korean Native Cattle) and to compare two different statistical algorithms for estimating genetic parameters. Data obtained from 1526 steers at Hanwoo Improvement Center and Hanwoo Improvement Complex Area from 1996 to 2001 were used for the analyses. The carcass traits considered in these studies were carcass weight, dressing percent, eye muscle area, backfat thickness, and marbling score. Estimated genetic parameters using EM-REML algorithm were compared to those by Bayesian inference via Gibbs Sampling to find out statistical properties. The estimated heritabilities of carcass traits by REML method were 0.28, 0.25, 0.35, 0.39 and 0.51, respectively and those by Gibbs Sampling method were 0.29, 0.25, 0.40, 0.42 and 0.54, respectively. This estimates were not significantly different, even though the estimated heritabilities by Gibbs Sampling method were higher than ones by REML method. Since the estimated statistics by REML method and Gibbs Sampling method were not significantly different in this study, it is inferred that both mothods could be efficiently applied for the analysis of carcass traits of cattle. However, further studies are demanded to define an optimal statistical method for handling large scale performance data.

• 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.

• Korean Journal of Poultry Science
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• v.39 no.3
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• pp.195-205
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• 2012

The objective of this study was to evaluate the effects of different levels of dietary ME on growth performance and carcass characteristics in two different strains of broiler chicken. A total of one thousand, 1-day-old A strain and R strain male chicks were randomly assigned into 8 treatments in a $2{\times}4$ factorial arrangement. They were fed iso-nitrogenic (CP 21%) crumbled diets formulated to contain metabolizable energy (ME) 2,950 to 3,250 kcal/kg in increment of 100 kcal/kg in the starter phase (1 to 21d) and iso-nitrogenic (CP 19%) pelleted diets containing same ME levels as in the finishing phase (22 to 38d). The body weight (BW) gain of chicks fed the lower ME diets (2,950 or 3,050 kcal/kg) were higher than those of the higher ME groups. The dietary energy level showed significant effects on feed intake and feed conversion rate (FCR) from 1 to 38 days of age (p<0.05). With the increment of dietary energy, feed intake tended to be reduced, whereas FCR was improved in the two strains of broiler chickens. The lowest FCR was observed at 3,250 kcal/kg diet groups in both of the two strains from 1 to 38 days of age. Feed intake and BW gain during 38 days were significantly affected by the strain factor. Increasing dietary energy up to 3,250 kcal/kg had no effect on the relative weights of breast meat and abdominal fat. The dietary energy and strains showed significant effects on the dressing percentage. There were no significant differences in various blood profiles except for GPT activity.

• Korean Journal of Poultry Science
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• v.50 no.2
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• pp.91-99
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• 2023

This study aimed to develop a high-productivity breed of Korean native Samgye chicken. We evaluated the production performance of six Korean native chicken combinations (KNC-SCYC, SCYD, SDYC, SDYD, SYYC, SYYD) and GSP-Hanhyup Korean native chickens, with Baeksemi chickens used as a control group. The performance test was conducted from hatching to 7 weeks of age on 756 chickens, and we measured survival rate, body weight, shank length, feed utility, and carcass yield. The overall survival rate was nearly 100% for all strains. However, body weight showed significant differences between strains at all ages (P<0.01), with Baeksemi weighing 863.8±76.9 g, GSP-Hanhyup weighing 804.7±72.5 g, and KNC-combinations weighing 543.0±61.8 g at 5 weeks of age. The duration needed to reach 850 g was estimated to be 34.5 days for Baeksemi, 37.5 days for GSP-Hanhyup, and 45.8-48.8 days for KNC-combinations. Carcass yield percentage was highest for KNC-SYYD combination at 63.3%, followed by Baeksemi at 60.4%, and GSP-Hanhyup at 56.1%. Shank length at 850 g body weight was 7.6 cm for KNC-SYYD combination, 7.8 cm for Baeksemi, and 8.0 cm for GSP-Hanhyup. The feed conversion ratio at 850 g body weight was 1.81 for Baeksemi, 2.17 for GSP-Hanhyup, and 2.27 for KNC-SCYC combination. Our results suggest that the KNC-SYYD combination and GSP-Hanhyup breed have the potential to be used in Samgye production due to their moderate growth performance, higher carcass yield, and shorter shank length, despite their lower growth productivity and feed efficiency when compared to Baeksemi.

• Korean Journal of Poultry Science
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• v.38 no.1
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• pp.51-57
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• 2011

This study was conducted to investigate the effects of supplementation diets of pine needle powder on performance, proximate composition, carcass characteristics, blood cholesterol concentration, TBARS (thiobarbituric acid reactive substance), WHC (water holding capacity), and shear force of chicken meat. Broiler chicks were fed diets for five weeks containing 0% pine needle powder (Control), 0.3% pine needle powder (T1), 0.6% pine needle powder (T2), and 0.9% pine needle powder (T3). Performance was no significant difference among treatment groups, but mortality was decreased in diets by the supplementation of pine needle powder than that of T1 and control. The moisture, crude protein, crude fat, and crude ash were no significant difference. The liver weight and abdominal fat was significantly decreased by the supplementation of pine needle powder compare to the T1 and control (P<0.05). The total cholesterol and LDL-cholesterol concentration of control was higher than treatment groups, and the HDL-cholesterol concentration and glucose of control was lower than treatment groups (P<0.05). The TBARS value was significantly decreased by the supplementation of pine needle compared to the control (P<0.05). In conclusion, these data indicate that 0.6% pine needle powder supplementation (T2) was most effective in decreasing mortality, total cholesterol and LDL-cholesterol and increasing HDL-cholesterol concentration.

• Korean Journal of Poultry Science
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• v.42 no.3
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• pp.205-214
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• 2015

This study aimed to investigate the effects of reducing feed intake on performance and meat quality in old laying hens. A total of 200 Hy-Line Brown laying hens (100 weeks old) were randomly allotted to five dietary treatments: control (100% daily feed intake), 90%, 60%, 50%, and 20% daily feed intake. Each treatment was replicated four times with 10 birds per replication and two birds per cage. Ten-bird units were arranged according to a randomized block design. The feeding trial lasted for 4 weeks under a 16L:8D lighting regimen. The results indicated that the daily feed intake correlated with hen-day egg production and feed conversion ratios (P<0.05). The carcass yields and partial ratios were also correlated with daily feed intake (P<0.05). The levels of leukocytes (without basophils) were higher in the 50% and 20% daily feed intake groups than in the other groups. The concentrations of dry matter, crude ash, crude fat, and crude protein, water holding capacity, cooking loss, and fatty acids in the breast meat did not decrease as the daily feed intake decreased. In conclusion, reducing daily feed intake decreased laying performance and carcass yield but had no effect on breast meat quality.