• Korean Journal of Agricultural Science
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• v.46 no.2
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• pp.395-404
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• 2019

This paper investigated the changes in Hanwoo breeding farms and herds according to their farm size and farm types based on traceability data in the Hanwoo industry. The major results are summarized as follows. First, the notion that small sized farms are breeding farms and middle or large sized farms are fattening farms is wrong. The results show that middle or large farms are not only fattening cattle but also breeding female cattle. Based on cattle data for over 6 months and under the criteria of a female cow ratio of 10 and 90% using the 2/4 quarter of 2018, the results show that the ratio of fattening only farms is 5.7%, that of breeding only farms is 59.0%, and that of fattening and breeding farms is 36.1%. The ratios of fattening, breeding, and both are 13.3, 13.5, and 73.2%, respectively, for a farm size with over 100 cattle. Second, this study found that the ratio of breeding farms over total farms has been increasing continuously over the last 5 years. This trend is apparent in the middle or large sized farms. However, the birth rate of cows is relatively lower in the middle and large sized farms than in the small sized farms. Hence, we can infer that the demand for a detection system for standing estrus in female cattle will increase. Additionally, the government should prepare relevant policies to stabilize the managerial conditions of middle or large sized farms.

• Journal of Animal Science and Technology
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• v.49 no.6
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• pp.689-698
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• 2007

This study aims to estimate the genetic parameters for carcass traits on Hanwoo of breeding farmhouses using Animal Products Grading Service’s data of 428,812 cattle from 101 slaughterhouses nationwide from 2000 to 2005. Using carcass traits of carcass weight, eye muscle area, backfat thickness, marbling score, meat color and fat color that greatly influence Hanwoo's grade, the effects of carcass year, carcass season, sex and carcass region were estimated. Based upon carcass traits of carcass weight, eye muscle area, backfat thickness, marbling score and meat color that greatly influence Hanwoo’s grade, the heritabilities and genetic parameters were estimated of 17,578 Hanwoo slaughtered in 2005 with existing herdbook, where EM-REML algorithm was used in estimating genetic parameters. The mean and standard deviation of each carcass trait are 321.42±53.62kg, 76.25±10.43cm2, 9.96± 4.14mm, 3.75±2.00, 4.83±0.48 and 2.99±0.40, for carcass weight, eye muscle area, backfat thickness, marbling score, meat color and fat color, respectively. As a result of analysis on the effects of carcass year, the carcass weight, backfat thickness and meat color came out highest as 359.40±0.181, 9.82±0.017 and 4.90±0.002, respectively in 2004. As a result of analysis on the effects of carcass season, the carcass weight and eye muscle area came out highest as 345.88±0.144 and 79.57±0.033 respectively in spring, and the backfat thickness was highest as 8.78±0.013 in winter, and the meat color and fat color slightly came out higher as 4.88±0.002 and 2.96±0.001 in fall, while the marbling score was highest as 3.29±0.006 in summer. The results of the analysis on the effects of sex indicated that the backfat thickness and fat color were highest as 10.53±0.010 and 3.07±0.001 in cow, the carcass weight came out highest in Hanwoo steer as 368.03±0.068kg, the eye muscle area were highest as 82.96±0.042 in bull, and the marbling score was highest as 4.19±0.007 in steer, and the meat color was highest as 4.89±0.001 in cow. Regarding the results of analysis on the effects of carcass region, the carcass weight, eye muscle area,

• Journal of Life Science
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• v.21 no.9
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• pp.1251-1258
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• 2011

Multiparous Hanwoo cull cows have been generally regarded to have poor meat quality compared to young and primiparous Hanwoo in Korea, and there have been few studies attempting to understand various feeding programs for the multiparous Hanwoo cull cow. In this study, the effects of a feeding program consisting of two different diets for multiparous Hanwoo cull cows on meat production and quality were tested in comparison to a commercially used diet. Diets for treatment consisted of two levels of crude protein contents, 14.28% and 12.70% for early fattening and finishing, respectively. For a control, commercially used fattening feed (12.39% crude protein) was used. Feeding trials were performed at three different farms. In farm A, 29 herds of multiparous Hanwoo cull cows were used for the treatment group and 3 herds for the control. In farms B and C, the number of animal herds for treatment and control were 8 vs. 3 and 11 vs. 4 herds, respectively. Experiment diets were fed for an average of 211 days and in treatment, early fattening diet was fed for 4 months and then finishing feed was fed until slaughter. Average daily gains, thickness of back fat, area of Longissimus dorsi, carcass weight, index of carcass weight, intramuscular fat, meat color and texture were analyzed after slaughter. Random effect model [8] was employed in effect analysis. Positive effects of treatment were found in terms of average daily gain, back fat thickness, Longissimus dorsi area, carcass weight, and intramuscular fat. Carcass yield index, meat color and texture showed a negative effect. In this study, significant results were not found in all factors analyzed because the variance between experiment farms was large, however the 90% confidence interval of summary effects of ADG, back fat thickness, Longissimus dorsi area and carcass weight were significant and that of carcass yield index, intramuscular fat, meat color and texture were less so. Conclusively, a high protein diet fed early during the fattening period in multiparous Hanwoo cull cows could have positive effects on meat production.

• Journal of Embryo Transfer
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• v.16 no.3
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• pp.183-191
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• 2001

This study was designed to establish the superior method for IVF embryos from DNA marker-proved Hanwoo cattle. DNA markers related to marbling score were identified using DNA fingerprinting with Ml3 probe and restriction enzyme Hae III. Oocytes were aspirated from unstimulated. immature ovarian follicles using a combined method of rectal ovarian-palpation and transvaginal ultrasound-guidance(6.5MHz) under local abesthesia. The aspirated oocytes were washed twice with fresh D-PBS containing 5% FBS and were rewashed 4 to 5 times with TCM-199 containing 5% FBS. A morphological grade of I to IV was assigned to each oocyte. Data were analysed using the GLM procedure of SAS. Mean number of follicles identified on ultrasound was 5.5 $\pm$2.9 in right and 4.3 $\pm$2.8 in left ovaries, respectively. The highest follicles(16.6$\pm$2.6) were found in 5101 cow compared to others. Recovery rate of follicular oocytes in individual cow was highest in 5101 cow with 89.3% in > 2mm and 94.0% in $\leq$ 2mm follicles. Total recovery rate was significantly(P<0.01) higher in $\leq$ 2mm(85.7%, 130/154) than > 2mm follicles(74.2%, 201/271). Significantly more oocytcs of Grade IV were recovered from > 2mm follicles. Mean number follicles recovered was 4.8$\pm$3.7. 3.0$\pm$3.4 and 0.3$\pm$0.6 in $\leq$2mm, 2~6mm and $\geq$6mm follicles. respectively. Our results imply that the more fertilizablc oocytes can be recovered from invisible-immature follicles by the combination of simultaneous rectal ovarian-palpation and ultrasound-guided approach in Hanwoo cattle.

• Journal of Embryo Transfer
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• v.17 no.2
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• pp.153-162
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• 2002

In order to develop the breeding techniques to increase Hanwoo (Bos taurus coreanae) population, the present study was performed 1) to establish the treatment protocol on reproductive disorders with GnRH or PGF／sub 2$\alpha$／, 2) to improve intraovarian PG $F_{2}$$\alpha$／ administration for reducing open period. Among total of 43 diagnosed, high percentage of cows (41.9％, 18 cows) were diagnosed as silent heat, followed by inactive ovaries (32.6％, 14 cows), ovarian cysts (9.3％, 4 cows), persistent corpus luteum (7.0％, 3 cows), endometriosis (4.7％, 2 cows), pyometra (2.3％, 1 cow) and luteal cysts (2.3％, 1 cow). To treat silent heat, 18 cows were administrated with 25 mg PGF／sub 2$\alpha$／, heat-detected, artificially inseminated and monitored pregnancy. All treated cows were heat-detected and 16 cows (88％) were successfully pregnant. With 200 $\mu\textrm{g}$ GnRH treatment, 7 cows (70％) with inactive ovaries and 3 cows (75％) with ovarian cysts were successfully pregnant. Administration with 25mg PGF／sub 2$\alpha$／, successfully treated 3 cows (100％) with persistent corpus luteum and 1 cow (100％) with luteal cysts, followed by 100％ pregnancy rate. With the combined treatment of 25 mg PG $F_{2}$$\alpha$／and antibiotics, 2 cows (100％) with endometriosis were effectively treated and got pregnant after. artificial insemination (AI). In order to reduce open period, 5 mg PGF／sub 2$\alpha$／ was administrated intraovarian to 20 days cows after delivery, heat-detected, artificially inseminated and monitored pregnancy. In the first experiment, in order to recover uterus, 5mg PGF／sub 2$\alpha$／were administrated, followed by administration of 5mg PGF／sub 2$\alpha$／ at the interval of 14 days. As results, 74％ (17／23 cows) of pregnancy rate after AI. In order to further reduce the open period, 5 mg PGF／sub 2$\alpha$／was administrated at the interval of 11 days without the period of uterus recovery, resulted in 94％ (16／17 cows) pregnancy rate. In conclusion, these results showed that PGF／sub 2$\alpha$／ and GnRH treatment were effective hormonal treatment resume in Hanwoo with various reproductive disorders. In addition, modified protocol of intraovarian PGF／sub 2$\alpha$／ administration could be the effective method for reducing the open period.

• Reproductive and Developmental Biology
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• v.36 no.1
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• pp.27-32
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• 2012

This study was carried out to investigate artificial insemination (AI) failure status and frozen semen characteristics in Korean proven bulls' number (KPN) semen used for AI of Hanwoo cows in Gangwon East region (Gangneung, Donghae, Taebaek, Samcheok, Sokcho, Yangyang, Goseong). Among semen used for AI, AI failure rate showed lowest at KPN506 (27.6%), whereas highest at KPN593 (77.2%). Correlations of AI failure in between Korean proven bulls semen and cows was 0.2941, which means that AI failure rate of Korean proven bulls semen may have respectable effect on reproduction of Hanwoo cow. In addition, present study was conducted to investigate spermatozoal viability rate, ruptured acrosome rate and active mitochondria in frozen Korean proven bulls semen with flow cytometry. The semen of KPN593 showed significantly ($p$<0.05) higher viability rate in KPN593 (30.49%) than that in KPN637 (37.34%). Furthermore, percentage of ruptured acrosome was lower in KPN637 as 21.37% than in KPN637 (21.37%), but it was not statistically significant. In conclusion, these results indicate that choice of Korean proven bulls semen may correlate positively with conception rate in Hanwoo cow. Therefore, KPN with high AI failure rate might be avoid to increase conception rate and characteristics of frozen semen might be evaluated before its use for AI.

• Korean Journal of Veterinary Service
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• v.31 no.1
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• pp.79-86
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• 2008

In this study two stage investigation was used for seroprevalence of Neospora caninum in cattle between January, 2005 and November, 2007; first stage was to examine positiveness of the farms selected randomly, second was to test all individual cow in positive farms. A total of 850 sera were collected from 170 farms for the first stage, and positive rate of farm and head were 23.5% (40/170farms) and 7.5% (64/850heads), respectively. Seroprevalence of Holstein cattle was much higher than that of Hanwoo. In second stage positive rate of cow was 18.9% (246/1,303head), but seroprevalence of farm was very variable (1 - 90.5%). It was supposed that 3 farms with high positive rate had some risk factors to be infected; raising dogs in the same farm, location of hill-side where is easy to contact with wild animals.

• Journal of Embryo Transfer
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• v.18 no.1
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• pp.81-84
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• 2003

This study was performed to produce Hanwoo-fetal fibroblast cell clone transferred to Holstein recipient. It was coming on the parturition but didn't show parturition signs until 272 days from the embryo transfer. For the induction of normal parturition, dexamethasone (20 mg) were injected with IM on 272 day and PG $F_{2a}$ (25 mg) plus estradiol (20 mg) was injected with IM after 24hrs. Forty-eight hours after dexamethasone injection, we could find parturition signs and delivered healthy male of offspring (40 kg) about 50 hrs after it's injection. However the recipient was showed retention of afterbirth.h.

• Korean Journal of Agricultural Science
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• v.46 no.1
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• pp.27-31
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• 2019

It is well documented that intensive selection in dairy cattle for economic value such as increased milk yield led to a decline in reproductive performance. Recent studies using genome-wide association studies (GWASs) discovered candidate genes involved in the lower fertility including embryo development and conception rates. However, the information, which showed a lower reproductive performance, is limited to dairy cattle, especially Holstein, and the candidate genes were not examined in the Korean native cattle Hanwoo which has been intensively selected and bred for meat in the last few decades. We selected the candidate genes WBP1 and PARM1 reported to be associated with cow and/or heifer conception in dairy cattle and analyzed the genotype because those genes have non-synonymous single nucleotide polymorphisms (SNPs). To determine the single base change, we used the high resolution melting (HRM) assay which is rapid and cost-effective for a small number of genes. We found that most heifers with higher conception (1: service per conception) have the AA genotype coding Threonine rather than Proline in the WBP1 gene. We did not detect an association for a SNP in PARM1 in our analysis. In conclusion, the genetic variation of WBP1 can be used as a selective marker gene to improve reproductive performance, and HRM assay can be used to identify common SNP genotypes rapidly and cost effectively.

• Journal of The Korean Society of Grassland and Forage Science
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• v.34 no.4
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• pp.283-287
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• 2014

This experiment was conducted to determine methane production and emission factors for a range of roughage diets fed to Hanwoo cows at a level of maintenance energy requirement. Seven cows were fed mixed hay only, 12 cows were fed mixed hay containing 30~50% rice straw and 6 cows were fed a mixed hay diet supplemented with 1.0 kg of wheat bran. Each cow was placed in a metabolic crate for 10 consecutive days, including last 7 days for sampling of feces and urine. At the end of the sampling period, the cows were transferred to an open-circuit respiration chamber for 24 consecutive hours. Methane conversion rate (5.5~6.2%, mean value = 5.8%) and emission factor (33.6~38.6 kg/head/year, mean value = 35.2) were not significantly affected by the diets although the mixed hay only diet resulted in 11 and 15% higher respective rates than the other two. However, in light of the many assumptions that forage with good quality might reduce methane production, additional experiments should be required for participation in the greenhouse gas emission trading system.