• Asian-Australasian Journal of Animal Sciences
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• 제27권2호
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• pp.155-160
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• 2014

The purpose of this study was to estimate genetic parameters of ultrasound measurements for longissimus dorsi muscle area (LMA), backfat thickness (BFT), and marbling score (MS) in Hanwoo cows (N = 3,062) at the ages between 18 and 42 months. Data were collected from 100 Hanwoo breeding farms in Gyeongbuk province, Korea, in 2007 and 2008. The cows were classified into four different age groups, i.e. 18 to 22 months (the first pregnancy period), 23 to 27 (the first parturition), 28 to 32 (the second pregnancy), and 33 to 42 (the second parturition), respectively. For each age group, a multi-trait animal model was used to estimate variance components and heritabilities of the three traits. The averages of LMA, BFT, and MS measurements across the cows of all age groups were 50.1 $cm^2$, 4.62 mm, and 3.04, respectively and heritability estimates were 0.09, 0.10, and 0.08 for the respective traits. However, when the data were analyzed in different age groups, heritability estimates of LMA and BFT were 0.24 and 0.47, respectively, for the cows of 18 to 22 months of age, and 0.21 for MS in the 28 to 32 months old cows. When the cows of all age groups were used, the estimates of genetic (phenotypic) correlations were 0.43 (0.35), -0.06 (0.34) and 0.21 (0.32) between LMA and BFT, LMA and MS, and BFT and MS, respectively. However, in the cow age group between 28 and 32 (18 and 22) months, the estimates of genetic (phenotypic) correlations were 0.05 (0.29), -0.15 (0.24) and 0.38 (0.24), for the respective pairs of traits. These results suggest that genetic, environmental, and phenotypic variations differ depending on cow age, such that care must be taken when ultrasound measurements are applied to selection of cows for meat quality.

• 농업과학연구
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• 제45권3호
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• pp.463-473
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• 2018

The objective of this study was to investigate the effects of dietary hydrolysable tannin on growth performance and methane emissions of Hanwoo beef cows. Fifteen cows participated in a seven-week experiment. The cows were stratified by initial methane emissions and assigned to one of two treatments: Control and tannin supplementation. Commercial hydrolysable tannin was top-dressed to a concentrate mix at 3 g/kg based on the dry matter. Enteric methane production was measured for 4 consecutive days at 1 week before and 1, 3 and 7 weeks after the initiation of the experiment using a laser methane detector. The feed intake was measured daily during the methane measurement periods and an additional two days prior to each measurement. The body weight of the cows was measured every 4 weeks. Hydrolysable tannin had no effect (p > 0.05) on body weight, average daily gain, dry matter intake (DMI) and feed conversion ratio. After one week, the methane emission of the tannin supplementation group was 3.66 ppm-m / kg DMI, which was about 3.4% lower (p = 0.078) than that of the control group; however, this tendency disappeared at 3 weeks after the start of the experiment (p > 0.05). The results of this study show that hydrolysable tannin supplementation can reduce enteric methane emissions for a limited period in Hanwoo beef cows. More research, however, is needed to determine the optimal level of hydrolysable tannin supplementation to reduce enteric methane emissions for a longer period without adversely affecting the animal performance of Hanwoo beef cattle.

• Reproductive and Developmental Biology
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• 제34권3호
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• pp.213-216
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• 2010

This study was carried out between November 2008 and October 2009 in the experimental farm of Chunnam National University to investigate the effect of feeding of Sudangrass silage on the reproductive performance of Hanwoo cows. Two diets, rice straw or Sudangrass silage separately from concentrate were fed 19 Hanwoo cows. In control group (=CON), cows (n=9) were fed 5 kg (/head) rice straw and 3 kg (/head) commercial diet. In Sudangrass silage group (=SGS), cows (n=10) were fed 12.5 kg (/head) Sudangrass silage and 1 kg (/head) commercial diet. 1. Days to post-partum insemination were $78.8{\pm}25.3$ days for CON and $84.7{\pm}24.6$ days for SGS group and days to post-partum conception in CON or SGS were $90.1{\pm}24.1$ and $87.7{\pm}26.8$ days, respectively. 2. Post-partum conception rates for first service in CON or SGS was 66.7% and 90.0%, respectively, and caving interval was $375.1{\pm}46.7$ days for CON and $370.2{\pm}34.4$ days for SGS group. 3. Body Condition Scores of Hanwoo cows at artificial insemination was 5.36 for CON group and 4.93 for SGS group.

• Reproductive and Developmental Biology
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• 제33권3호
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• pp.179-182
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• 2009

This study was carried out between November 2007 and October 2008 in the experimental farm of Chunnam National University to investigate the effect of feeding of whole crop barley silage on the reproductive performance of Hanwoo heifers and cows. Two diets, rice straw or whole crop barley silage separately from concentrate were fed 11 Hanwoo heifers and 26 Hanwoo cows. In control group (=CON), heifers (n=6) and cows (n=13) were fed 7 kg (/head) rice straw and 4 kg (/head) commercial diet. In whole crop barley silage group (=WBG), heifers (n=5) and cows (n=13) were fed 8 kg (/head) whole crop barley silage and 1 kg (/head) commercial diet. 1. Conception rates for first service in CON or WBG heifers were 66.7% (4/6) and 60.0% (3/5), respectively, and the services per conception cows were $1.5{\pm}0.2$ for CON and $1.4{\pm}0.2$ for WBG group. 2. Days to post-partum insemination were $106.6{\pm}26.3$ days for CON and $85.6{\pm}12.6$ days for WBG group, and days to post-partum conception in CON or WBG were $128.4{\pm}27.1$ and $96.8{\pm}16.8$ days, respectively. 3. Post-partum conception rates for first service in CON or WBG were 76.9% (10/13) and 84.6% (11/13), respectively, and caving interval was $418{\pm}50.7$ days for CON and $392.8{\pm}20.7$ days for WBG group.

• Animal Bioscience
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• 제36권4호
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• pp.591-600
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• 2023

Objective: We aimed to evaluate the efficacy of a modified Double-Ovsynch protocol vs artificial insemination following estrus detection (AIED) for the enhancement of reproductive performance in Hanwoo cattle. Methods: Four hundred twelve Hanwoo cows were allocated to two treatment groups. The first group of cows were administered gonadotropin releasing hormone (GnRH) on Day 36 (±0.6), prostaglandin F_2α (PGF_2α) on Day 46 (8 to 12 days later), and GnRH on Day 49, which was followed by Ovsynch, consisting of an injection of GnRH on Day 56, PGF_2α on Day 63, and GnRH 56 h and timed AI (TAI) 16 h later (modified Double-Ovsynch group, n = 203). The second group of cows underwent AIED (AIED group, n = 209) and were designated as controls. Results: The pregnancy per AI 60 days after the first AI was higher in the modified Double-Ovsynch (68.5%) than in the AIED (56.5%) group, resulting in a higher probability of pregnancy per AI (odds ratio: 1.68, p<0.05). Moreover, cows in the modified Double-Ovsynch group were more likely (hazard ratio: 1.28, p<0.05) to be pregnant by 150 days after calving than cows in the AIED group, and this difference was associated with a lower mean number of AIs per conception (1.27 vs 1.39, p<0.05) and a shorter median interval between calving and pregnancy (72 vs 78 days, p<0.1). Conclusion: The modified Double-Ovsynch protocol, adjusted according to the herd visit schedule, can be readily used to increase the pregnancy per AI following the first AI and to shorten the interval between calving and pregnancy in beef herds.

• Journal of Animal Science and Technology
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• 제62권6호
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• pp.959-959
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• 2020

• Journal of Animal Science and Technology
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• 제52권6호
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• pp.499-504
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• 2010

This study was conducted to determine the effects of ruminally protected amino acid-enriched fatty acids (RPAAFA) on body weight gain, feed intake and carcass characteristics of fattening Hanwoo cows. Twenty eight Hanwoo cows, $6.0{\pm}1.7$ years old and weighing an average of $463.2{\pm}77.6\;kg$, were used for 4 months. Animals were fed a basal diet supplemented with RPAAFA at 0 g (control) and 100 g (treatment), respectively. Average daily gain, dry matter intake and feed conversion ratio were not different among the control and treatment. The supplementation of RPAAFA did not affect carcass weight and rib eye areas. Quality grade score ($1^{++}$, $1^+$ and 1) for treatment was higher in RPAAFA supplemented group compared with the control, whereas no differences appeared in meat color, fat color, texture and maturity. Thus present results indicate that supplementation of RPAAFA may be recommended for producing high quality beef from fattening Hanwoo cows.

• 한국수정란이식학회지
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• 제23권3호
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• pp.167-175
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• 2008

This study was performed to investigate the result that in-vivo or in-vitro embryos of Hanwoo cows were transferred to Holstein cows. Seventeen Hanwoo cows were used as donors for production of in-vivo embryos and fresh hanwoo in-vivo embryos were transferred to 1,150 Holsteins. And 2 embryos were transferred to 188 Holstein recipients to produce twin calves. Diagnosis on pregnancy was performed by rectal palpation at $60\sim90$ days after transfer. The pregnancy rate of Holstein recipients was 55.8% after transfer with Hanwoo in-vivo embryos and 38.2% after transfer with Hanwoo in-vitro embryos. The delivery rate of pregnant Holstein recipients was 88.4% after transfer with Hanwoo in-vivo embryos and 75.6% after transfer with Hanwoo in-vitro embryos. The rate of delivery of Holstein recipients transferred with two Hanwoo embryos was 36.2% and the rate of twin production was 25.9%. The rate of twin production by embryo transfer with in-vivo embryos was 30.4%, whereas the fate with in-vitro embryos was 15.6%. The pregnancy rate according to the grade of corpus luteum of Holstein recipients transferred with Hanwoo in-vitro embryos was 41.5 and 36.0% for A and B grade, respectively. The pregnancy rate according to the transfer in site in the uterine lumen of recipients was 40.9 and 32.7% for anterior and middle site, respectively. The pregnancy rate according to day of embryo transfer after estrus of recipients was 45.5, 38.8 and 39.7% for day 6, day 7 and day 8, respectively. There was difference of pregnancy rate according embryo transfer technician ($30.5\sim45.8%$) individual dairy farm ($21.1\sim51.0%$). These results are supposed to indicate that the rate of pregnancy after transfer with Hanwoo embryos to Holstein recipients was similar to that within the same breed, and consequently that this method would be beneficial to enhance the productivity in Hanwoo reproduction.

• Asian-Australasian Journal of Animal Sciences
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• 제17권9호
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• pp.1241-1245
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• 2004

Two separate trials were conducted to determine effects of dietary level of whole flaxseed (WFS; 0, 10 and 15%) on feed intake, weight gain, and carcass yield and quality of Korean Hanwoo cattle. The daily gains of bulls (Trial 1) were not different among treatment groups, but those of cows (Trial 2) fed WFS 15% were higher (p<0.01) than others. Feed intake of both bulls and cows tended to decrease as dietary level of WFS increased. However, feed conversion ratio (feed/gain) of bulls tended to be improved by dietary inclusion of WFS and was significantly improved (p<0.01) in cows by increasing level of WFS. Neither carcass weight nor dressing percentage were affected by WFS level. Back fat thickness of bulls was decreased (p<0.01) by dietary inclusion of WFS and the same trend was observed in cows without statistical significance. Loin-eye area of bulls was not different among treatment groups but was significantly higher (p<0.01) in cows fed WFS. Carcass yield and quality were not improved by WFS addition. The results indicate that WFS is an acceptable fat source in diets of finishing beef cattle to increase energy density without any adverse effects.

• 한국유기농업학회지
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• 제31권4호
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• pp.327-341
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• 2023

The Ministry of Agriculture, Food and Rural Affairs, Hanwoo Association and Nonghyup have discussed proactive reduction measures for cows in response to concerns about an oversupply of hanwoo to ensure supply stability. This study aims to empirically analyze whether the cow fattening support program is being implemented in line with its objectives. Based on the analysis of beef traceability data, the slaughter age of participating cows was reduced by 7.6 to 14.7 months compared to non-participating cows. And heifer was reduced 1.5 months in their slaughter age. In case of parity, participating cows showed a reduction of 1.4 compared to non-participating cows. Through the SUR model, an analysis was conducted to examine the effect of the cow fattening support program on the suppression of calf production numbers. The analysis results showed that the calf production numbers are positively influenced by the number of fertile cow and the quantity of semen sales. Furthermore, it is estimated that calf production decreased as the fat index increased, and during the period when the cow fattening support program was implemented, an average monthly suppression of 3,558 calves was observed.