• Journal of Animal Science and Technology
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• v.64 no.1
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• pp.143-154
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• 2022

This study was conducted to evaluate the relationship among market weight, slaughter age, yield grade, and primal cut yield in Hanwoo. A total of 403 Hanwoo (Korean native cattle) was assessed for carcass traits such as carcass cold weight, backfat thickness, ribeye area, dressing percentage, yield index, and marbling score. The production yield of the individual major primal cuts of Hanwoo beef was also measured. Carcass cold weight, ribeye area, and backfat thickness, which affect meat quality increased with increased market weight (p < 0.05). The production yield of the ten major primal cuts also increased with increased market weight (p < 0.05). In terms of slaughter age, carcass cold weight, ribeye area, and backfat thickness all increased from 25 months to 28-29 months, and the production yield of all prime cuts also increased with increasing slaughter age. According to the meat yield grade, carcass cold weight and backfat thickness increased from grade A to grade C, although the ribeye area was not affected. The combined findings of the study suggest that slaughtering Hanwoo at the weight of 651-700 kg and 701-750 and age of 28.23 and 29.83 months could be desirable to achieve the best quality and quantity grade of Hanwoo beef. However, the positive correlation of carcass cold weight and backfat thickness, and the negative correlation of the yield index according to primal cuts yield indicated that it is necessary to couple the slaughtering management of cattle with improved genetic and breeding method of Hanwoo to increase the production yield of the major prime cuts of Hanwoo beef.

• Food Science of Animal Resources
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• v.33 no.3
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• pp.305-316
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• 2013

The strategy for increasing the palatability of Hanwoo beef through fattening could lead to a decline in yield grade. The aim of this study was to examine the meat quality traits of Longissimus dorsi (LD) muscle from carcasses of Hanwoo steers at different yield grades. A total of 246 Hanwoo steers was divided into the following yield grades: A (n=77), B (n=76) and C (n=93). Meat quality traits, including proximate composition, cholesterol content, nucleotide content, dipeptide content, creatine and creatinine, free amino acid content, fatty acid composition, instrumental meat color, pH, water holding capacity, drip loss, cooking loss, and sensory qualities of the LD muscle from the 3 yield grades of Hanwoo carcasses were measured. The decline in yield grade from A to C resulted in an increase in crude fat and cholesterol content as well as a decrease in inosine 5'-monophosphate and aspartic acid in the LD muscle (p<0.05). In terms of fatty acid composition, the LD muscle from yield grade A had higher SFA and PUFA and lower MUFA content than that from yield grade C (p<0.05). However, the ratio of PUFA/SFA and n-6/n-3 did not differ among LD muscles from the 3 yield grades. There were no significant differences among other meat quality traits in relation to the yield grade. In conclusion, we suggest that the changes of substances related with health and flavor can be considered in order to obtain better quality Hanwoo beef.

• 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.

• Journal of Embryo Transfer
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• v.23 no.4
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• pp.291-298
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• 2008

We separately cultured follicular oocytes collected from individual ovaries of slaughtered Korean native cows and examined both the embryonic development rate and pregnancy rate after embryo transplantation according to the meat yield and quality grades of the source beef carcass. Oocytes from meat yield grade B cows exhibited a higher fertilization rate and embryonic developmental rate to the eight-cell stage than oocytes from grade A or C animals (p<0.05), but there was no significant difference in rate of development to the blastocyst stage among meat yield grades A, Band C. The oocyte cleavage rate and development rate to the eight-cell stage from meat quality grade 3 cattle was higher than grades 1++, 1+, 1 and 2 (p<0.05). Embryos derived from grade animals displayed a development rate to the blastocyst stage of 19.4%, which was also higher than all other meat quality grades (p<0.05). Transplantation of in vitro-cultured oocytes from meat yield grade A ovaries led to a higher pregnancy rate (64.2%) than in vitro-cultured oocytes from meat yield grade B ovaries (56.5%), but there was no significant difference between the two groups in pregnancy or abortion rates. In conclusion, embryonic development rate and pregnancy rate has a close relation to meat quality grades of the source beef carcass, this results is to give information for the Korean native cows improvement of breed.

• Asian-Australasian Journal of Animal Sciences
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• v.15 no.4
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• pp.591-595
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• 2002

Three hundred thirty five progeny testing steers of Korean beef cattle were evaluated ultrasonically for back fat thickness (BFT), longissimus muscle area (LMA) and intramuscular fat (IF) before slaughter. Class measurements associated with the Korean yield grade and quality grade were also obtained. Residual standard deviation between ultrasonic estimates and carcass measurements of BFT, LMA were 1.49 mm and $0.96cm^2$. The linear correlation coefficients (p<0.01) between ultrasonic estimates and carcass measurements of BFT, LMA and IF were 0.75, 0.57 and 0.67, respectively. Results for improving predictions of yield grade by four methods-the Korean yield grade index equation, fat depth alone, regression and decision tree methods were 75.4%, 79.6%, 64.3% and 81.4%, respectively. We conclude that the decision tree method can easily predict yield grade and is also useful for increasing prediction accuracy rate.

• Food Science of Animal Resources
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• v.28 no.5
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• pp.604-609
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• 2008

Analyses were conducted to estimate carcass component of yield grade factors by sex and live weight class and to develop the prediction equation of retail product weight by sex in Korean native cattle (Hanwoo). Data from 42,113 Hanwoo carcasses were used to estimate the traits of yield grade factor and an additional 1,066 carcasses were used to develop the prediction equation of retail meat weight. The average of fasting weight of cow, bull and steer were 529 kg, 596 kg, and 634 kg respectively. Carcass weight (CW), backfat thickness (BFT), loineye area (REA), Index score of wholesale meat and yield grade were significantly (p<0.01) affected by sex and live weight. The lean meat percentage, fat percentage and bone percentage based on the weight of cold carcasses were significantly different (p<0.05) between sex groups. The equation of predicting the retail meat product from this study could be expressed as a multiple regression $Y=-4.18+0.63{\times}CW\;(kg)-0.17{\times}BFT\;(cm)+0.16{\times}REA\;(cm^2)$, $R^2=0.93$. Among the independent factors, the BFT was the highest contributor to the prediction equation. Using the equation from this study should allow for rapid, precise and cost-effective assessment of the retail product in Hanwoo beef carcasses.

• Journal of Animal Science and Technology
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• v.45 no.1
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• pp.151-156
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• 2003

This study was conducted to provide the information for the carcass grading properties of imported beef cattles fed in Korea. The cattles from 4 different breed such as Hereford, Angus, Murray Grey, Hereford${\times}$Angus were imported and slaughtered at 700kg(24 month). The Yield and Quality grading characteristics for 10 cattles from each breed were evaluated. Carcass weight of Murray Grey was lower than the other breed(p<0.05). The thickness of backfat was the lowest for Hereford(13.7mm) and followed by Hereford${\times}$Angus(17.30mm), Angus(18.20mm) and Murray Grey(18.90mm). Hereford had the highest Yield index(64.63%) and Murray Grey had the lowest Yield index(62.43)(p<0.05). The frequency percentages of marbling degree for Angus having the 1++ over degrees were 50% which was the highest among the breed. In the frequencies of final carcass grades, Hereford produced 30% of B grade and 70% of C grade in Yield grade and the 3 grade produced in Quality grade. All carcasses of Angus were graded as the grade C in Yield grade and 20% carcasses of Angus had the 2 grade and 80% carcasses had the 3 grade in Quality grade. Murray Grey produced 10% of grade B and 90% of grade C in Yield grade and produced 10% of the 2 grade and 90% of the 3 grade in Quality grade. The Hereford${\times}$Angus produced 100% of grade C in Yield grade and 100% of the 3 grade in Quality grade.

• Asian-Australasian Journal of Animal Sciences
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• v.14 no.1
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• pp.123-135
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• 2001

Application of growth promoters by means of implantation or supplementation to the diets has been routine in the beef cattle industry of many countries for the better performance in growth and improvement of feed efficiency. Anabolic implants (zeranol, trenbolone acetate, and estradiol with testosterone or progesterone) have generated various positive effects. Zeranol implantation, in general, improved average daily gain (ADG), feed conversion (FC), dressing percentage (DP) and yield grade (YG) of cattle, and increased dry matter intake (DMI). Trenbolone acetate with or without estradiol also increased mean values of ADG and loin eye area (LEA) but reduced DMI and improved FC of cattle. Estradiol with testosterone or progesterone increased ADG and DMI. Anabolic implants, however, had minimal or negative effects on marbling or quality grade. The magnitude of the response to these anabolic implants in performance of beef cattle has varied depending on the type of implants, amount and duration of exposure, age of animals and combination of implants. Administration of bovine somatotropin improved ADG and FC, and decreased fat deposition. Ionophores improved FC in cattle from reduced DMI without great response to ADG. Supplementation of monensin and lasalocid reduced molar proportion of propionate. Monensin and lysocellin increased apparent absorption and retention of some minerals in cattle. Despite the improved cattle performance in growth and FC, results in beef quality from the application of the growth promoters appeared to vary or in conflict under a variety of environmental conditions.

• Journal of Animal Science and Technology
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• v.59 no.3
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• pp.6.1-6.6
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• 2017

Background: This study was aim to observe the effects of feeding mixed local hay (MH) consisted of 55% orchard grass (Dactylis glomerata L.), 35% tall fescue (Festuca arundinacea) and 10% red clover (Trifolium pratense) to Hanwoo steers on performance, carcass characteristics and meat quality (longissimus thoracis) compared with feeding imported timothy hay (TH) and local rice straw (RS). Results: Although no significant effects were found on animal performance and carcass yield grade, the carcasses of MH group had higher marbling score and quality grade than those of RS and TH group (P < 0.05). Therefore, higher fat content (P < 0.001), lower shear force and hardness value in the beef of MH group than that of other groups were observed. Furthermore, the beef of MH group had higher CIE $a^*$ value (redness) than that of other groups and feeding MH to Hanwoo steers lowered n-6 to n-3 fatty acids ratio in beef. Conclusions: Mixed hay provided benefits on meat quality and could be used for Hanwoo fattening program.

• Food Science of Animal Resources
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• v.30 no.6
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• pp.905-909
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• 2010

Two sets of data on carcass traits and beef cut parameters were used to investigate the relationships between carcass and beef cut measurements, which can be used to make predictions of retail cut percentages. One set had a total of 1,141 measurements of Hanwoo cattle of three different sex origins, which were slaughtered in an abattoir located at the National Institute of Animal Science, RDA, Korea from 1996 to 2008. To develop prediction models for retail cut percentage with higher accuracies than the current model, another set consisting of a total of 13,389 records of carcass and beef cut traits were collected from 30 abattoirs and butcheries in Korea from 2008 to 2009. Bulls yielded heavier and leaner carcasses than steers. High correlation coefficients were estimated between amount of body fat and percent retail cut (-0.82) as well as between back fat thickness (BF) and percent retail cut (-0.62). The amount of retail cut, however, was highly correlated with body weight before slaughter (BW, 0.95) or with cold carcass weight (CWT, 0.94). Relationships between percent retail cut and measurable beef yield traits, BF, loin eye area (LEA) or CWT varied by sex class, which must be considered for development of a prediction model with high accuracy. Models of data for all breeds and sexes fit the effects of breed, sex, and interaction of abattoir by butchers, whereas models of data for each breed and sex fit the effect of interaction of abattoir by butcher only. Due to possible future changes in back fat control, we performed a log transformation of BF. Our new models fit better than the currently used model.