• Asian-Australasian Journal of Animal Sciences
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• v.15 no.1
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• pp.111-116
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• 2002

This study investigated quantitative changes in the spaces between and within myofibrils and the impact of high and low voltage electrical stimulation on muscle ultrastructure as seen in electron micrographs. In addition, the relationships of these spaces and the impact to meat tenderness were investigated. The degradation of myofibrils during aging appeared to be localized across the muscle fibre. Structural deterioration of muscle fibres was evident 1 day post-mortem, involving the weakening in the lateral integrity of the myofibrils and Z-disc regions. Meat tenderisation, as shown by objective measurements, coincided with these increases in degradation, as assessed by the sum of the gaps between and within myofibrils. The results showed that the total size of gaps between and within myofibrils can be used as an indicator of meat tenderization during aging, but that ultrastructural alteration in electrically stimulated muscle had little relationship with meat tenderness.

• Korean Journal of Veterinary Research
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• v.32 no.1
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• pp.143-151
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• 1992

Sixty Four fresh and 142 frozen embryos of dairy cattle were transferred to synchronized dairy, beef or Korean Native Cattle nonsurgically at National Animal Breeding Institute from 1985 to 1990. The results obtained were as follows ; 1. The pregnancy rate of fresh embryos(39.1%) was higher than that of frozen embryos(32.4%) and average pregnancy rate was 34.5%. 2. The pregnancy rate of grade 1 embryos was higher than that of grade 2 embryos for both fresh(41.3% vs 33.3%) and frozen embryos(35.4% vs 25.6%). 3. The pregnancy rate according to development stage of fresh embryos was increased with maturity as 29.2%, 33.3%, 50.0% and 54.5% for morula, early blastocyst, blastocyst and expanded blastocyst, respectively. For frozen embryos, the pregnancy rate of blastocyst(44.4%) was higher than those of morula(31.3%) and early blastocyst(28.0%). 4. The pregnancy rate according go recipient-donor synchrony for fresh embryos was higher when the recipients exhibited estrus 1 day earlier than the donors(43.8%) than when the recipients exhibited estrus 1 day later than the donors(38.1%) or when the recipients and donors exhibited estrus at the same time(37.0%). For forzen embryos, the pregnancy rate was decreased when the recipients and donors exhibited estrus at the same time(37.9%), when the recipients exhibited estrus 1 day later than the donors(32.0%) and when the recipients exhibited estrus 1 day earlier than the donors(23.5%), in sequence. 5. The pregnancy rate of heifers was higher than that of cows for both fresh(50.5% vs 37.9%) and frozen embryos(39.7% vs 25.7%). 6. The pregnancy rate according to recipient breed for fresh embryos was higher in dairy cattle(42.1%) and beef cattle(40.%) than in Korean Native Cattle(33.3%). For frozen embryos, the pregnancy rate was decreased beef cattle(39.1%), dairy cattle(30.3%) and Korean Native Cattle(14.3%), in sequence. 7. The pregnancy rate according to equilibrium steps of glycerol and freezing rate was higher when transferred after 3-steps equilibrium and freezing by the rate of $0.3^{\circ}C$/min from $-6^{\circ}C$ to $-35^{\circ}C$ and $0.1^{\circ}C$/min to $-38^{\circ}C$(39.4%) than when transferred after 6-steps equilibrium and freezing by the rate of $0.5^{\circ}C/min$ from $-6^{\circ}C$ to $-30^{\circ}C$(30.3%).

• Proceedings of the Korean Society of Life Science Conference
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• 2005.04a
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• pp.93-93
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• 2005

• Asian-Australasian Journal of Animal Sciences
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• v.27 no.10
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• pp.1513-1520
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• 2014

The present aim was to investigate the effects of traditional Chinese medicine prescriptions (TCM) on body temperature, blood physiological parameters, nutrient apparent digestibility and growth performance of beef cattle under heat stress conditions. Twenty-seven beef cattle were randomly divided into three groups as following; i) high temperature control (HTC), ii) traditional Chinese medicine prescriptions I+high temperature (TCM I) and iii) traditional Chinese medicine prescriptions II+high temperature (TCM II) (n = 9 per group). The results showed that the mean body temperature declined in TCM II treatment (p<0.05). Serum $T_3$ and $T_4$ levels with TCM I and TCM II treatments elevated (p<0.05), and serum cortisol levels of TCM I treatments decreased (p<0.05), compared with the HTC group. Total protein, albumin, globulin in TCM II treatments elevated and blood urea nitrogen levels of both TCM treatments increased, but glucose levels of both TCM treatments decreased, compared with the HTC group (p<0.05). The apparent digestibility of organic matter and crude protein with TCM I treatment increased, and the apparent digestibility of acid detergent fiber elevated in both TCM treatments (p<0.05). Average daily feed intake was not different among three groups, however average daily gain increased and the feed:gain ratio decreased with both TCM treatments, compared with the HTC group (p<0.05). The present results suggest that dietary supplementation with TCM I or TCM II improves growth performance of heat stressed beef cattle by relieving heat stress responses and increasing nutrient apparent digestibility.

• Journal of Animal Environmental Science
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• v.14 no.3
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• pp.167-174
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• 2008

This survey was conducted to investigate housing types of Korean native cattle and beef cattle farms in Korea. The farm sized over 50 heads of cattle, 7,433 farms were surveyed. Regarding housing types for Korean native cattle and beef cattle, litter barn, freestall, mooring+litter ground and others accounted for 87.1, 9.8, 3.0, and 2.9 %, respectively. Most of Korean native cattle and beef cattle farms (94.7%) used litter floor rather than scraper. As for roof types, slate, panel, iron plate, galvanized plate, colored iron plate and sunlight represented 32.2, 13.7, 12.2, 10.2, 9.7, and 8.9 %, respectively. Open side wall type and winch curtain were 55.6, and 47.6 %, respectively. Bigger farms seemed to used more winch curtain than open style. Utilization period of automatic feeder, waterer, electric facility, and cooling facility was 6.7, 8.0, 8.5, and 6.0 years, respectively.

• Asian-Australasian Journal of Animal Sciences
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• v.22 no.2
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• pp.232-237
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• 2009

The expression of SGLT-1 mRNA has been reported in the small intestine of mammals and the rectum of chickens. However, the expression and functional significance of SGLT-1 in bovine rectum is not known. In this study, we studied the effects of fasting and grazing on SGLT-1 gene expression in biopsy epithelial tissue of bovine rectum. In Japanese Black beef cattle, i) SGLT-1 gene expression was measured by quantitative real-time PCR in the biopsy rectal epithelia samples obtained through an endoscope, ii) SGLT-1 gene expression in the rectal epithelial tissues increased at 48 and 72 h after fasting correlating with a decrease in body weight. iii) SGLT-1 gene expression decreased after one month from the start of grazing (May to June) and then stabilized until the end of the grazing period (June to October) in the rectal epithelial tissues of grazing cattle. In conclusion, it is clear that SGLT-1 gene expression in the rectal epithelial tissue is increased by a restricted dietary condition.

• Journal of Practical Agriculture & Fisheries Research
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• v.17 no.1
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• pp.3-20
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• 2015

Vitamin A exerts a broad range of effects on many essential life processes. But, since vitamin A is known to negatively affect the development of adipocytes, extensive research has been conducted to improve marbling score in beef cattle by feeding vitamin A-deficient diets. In Japan, the method of fattening Wagyu cattle using vitamin A-deficient diets has been widely adapted. Recently, the method of feeding vitamin A-deficient diets in Korean native cattle (Hanwoo) has been spread by feed companies and TMR plants. But proper guidelines in feeding vitamin A-deficient diets should be provided, otherwise it can adversely affect the health of cattle. To maximize marbling score, a controlled level of vitamin A in blood needs to be maintained and the proper period for feeding vitamin A-deficient diets should be adapted. This review was conducted to highlight the regulatory effects of vitamins A on adipocyte differentiation, and offer a potential guideline for improving beef quality grades in Hanwoo.

• Asian-Australasian Journal of Animal Sciences
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• v.31 no.7
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• pp.1043-1061
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• 2018

Intramuscular fat (IMF) content in skeletal muscle including the longissimus dorsi muscle (LM), also known as marbling fat, is one of the most important factors determining beef quality in several countries including Korea, Japan, Australia, and the United States. Genetics and breed, management, and nutrition affect IMF deposition. Japanese Black cattle breed has the highest IMF content in the world, and Korean cattle (also called Hanwoo) the second highest. Here, we review results of research on genetic factors (breed and sex differences and heritability) that affect IMF deposition. Cattle management factors are also important for IMF deposition. Castration of bulls increases IMF deposition in most cattle breeds. The effects of several management factors, including weaning age, castration, slaughter weight and age, and environmental conditions on IMF deposition are also reviewed. Nutritional factors, including fat metabolism, digestion and absorption of feed, glucose/starch availability, and vitamin A, D, and C levels are important for IMF deposition. Manipulating IMF deposition through developmental programming via metabolic imprinting is a recently proposed nutritional method to change potential IMF deposition during the fetal and neonatal periods in rodents and domestic animals. Application of fetal nutritional programming to increase IMF deposition of progeny in later life is reviewed. The coordination of several factors affects IMF deposition. Thus, a combination of several strategies may be needed to manipulate IMF deposition, depending on the consumer's beef preference. In particular, stage-specific feeding programs with concentrate-based diets developed by Japan and Korea are described in this article.

• Asian-Australasian Journal of Animal Sciences
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• v.28 no.3
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• pp.442-450
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• 2015

Climate temperature affects animal production. This study was conducted to evaluate whether climatic conditions affect beef carcass characteristics of Korean cattle steers. The monthly carcass characteristics of Korean cattle steers (n = 2,182,415) for 8 yr (2006 through 2013) were collected from the Korean Institute for Animal Products Quality Evaluation. Daily climate temperature (CT) and relative humidity (RH) data were collected from the Korean Meteorological Administration. Weather conditions in South Korea during summer were hot and humid, with a maximum temperature of $28.4^{\circ}C$ and a maximum RH of 91.4%. The temperature-humidity index (THI), calculated based on CT and RH, ranges from 73 to 80 during summer. Winter in South Korea was cold, with a minimum temperature of $-4.0^{\circ}C$ and a wind-chill temperature of $-6.2^{\circ}C$. Both marbling score (MS) and quality grade (QG) of Korean cattle steer carcasses were generally best (p<0.05) in autumn and worst in spring. A correlation analysis showed that MS and QG frequencies were not associated (p>0.05) with CT. Yield grade (YG) of Korean cattle steer carcasses was lowest (p<0.05) in winter (November to January) and highest in spring and summer (May to September). A correlation analysis revealed that YG frequency was strongly correlated ($r{\geq}0.71$; p<0.01) with CT and THI values. The rib eye area, a positive YG parameter, was not associated with CT. Backfat thickness (BT), a negative YG factor, was highest in winter (November and December). The BT was strongly negatively correlated ($r{\leq}-0.74$; p<0.01) with CTs. Therefore, the poor YG during winter is likely due in part to the high BT. In conclusion, YG in Korean cattle steer carcasses was worst in winter. QGs were not associated with winter or summer climatic conditions.

• Asian-Australasian Journal of Animal Sciences
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• v.19 no.7
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• pp.1004-1009
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• 2006

Four male crossbred native beef cattle (average body weight of 427.7 kg) were randomly allocated to four types of cassoy-urea pellet as a source of protein in concentrate according to a $4{\times}4$ Latin square design to determine effect of diets on ruminal fermentation and nutrient digestibility. The four types of cassoy-urea pellets contained cassava hay, soybean meal, urea and binding agent at 79.2:19.8:0:1 (27.9% CP dry matter), 78.4:19.6:1:1 (30.4% CP), 77.6:19.4:2:1 (33.0% CP) and 99:0:0:1 (23.8% CP) for dietary treatments; 1, 2, 3 and 4, respectively. All four concentrate mixtures contained similar crude protein levels (11% CP) and were fed to animals in two equal parts (0.5% of body weight per day) while urea-treated rice straw (5% urea) was given ad libitum. The experiment revealed that dietary concentrate treatments had no effect on dry matter intake while digestibilities of neutral-detergent fiber and crude protein were higher (p<0.05) in cattle fed dietary treatments 1, 2 and 3 than in cattle fed dietary treatment 4. Ruminal ammonia-nitrogen ($NH_3$-N), was higher and acetic acid concentration (C2) and ratio of C2 to propionic acid (C3) were lower (p<0.05) in cattle fed dietary treatments 1, 2 and 3 than in those on treatment 4. It is concluded that use of cassoy-urea pellet as a protein source in concentrates for cattle resulted in improvement of digestibility, ruminal fermentation and rumen ecology. Further research using cassoy-urea pellet in feeding trials with milking cows and fattening beef should be undertaken.