• Journal of The Korean Society of Grassland and Forage Science
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• v.18 no.1
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• pp.61-68
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• 1998

This research was canied out to investigate the effect of castration and injection time of sustained release recombinant bovine somatotropin(SR-rbST) on dry matter intake(DM1) and nutrient intake of surgically castrated 32 Holstein young bulls by growth stage. The main results were as follows: 1. DM intakes were not different between in bull and steer groups, but those in rbSTl and rbST2 were 7.88 and 7.65kg respectively, which were lower 6-9% compared to bull and steer groups. 2. Actual DM intake to DM requirement of Beef cattle(NRC) was 88.5~97.7%, while net energy intake was sufficient for NE requirement in all groups during all growth stage except rbST group during fmishing stage. 3. Overall mean concentrate intake to body weight in steer group was the highest as 1.94%, and then those in rbST groups were 1.87~1.89% which were higher 0.07~0.09% unit than in bull group. 4. Feed conversion ratios(DM) in bull, rbSTl and rbST2 groups were 8.29, 8.18 and 7.60kg respectively, which were improved 12.4, 13.9 and 22.6%, respectively, compared to steer group.

• Asian-Australasian Journal of Animal Sciences
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• v.12 no.8
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• pp.1316-1323
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• 1999

Extensive emphasis on milk and milk fat yields with no diversion for beef performance increased the yield efficiency of North American dairy cattle. Heavy demand for North American genetics followed national strain comparison trials in Poland, and US and Canadian dairy cattle and germplasm still are an important source of genetics for many countries. Genetic improvement has accelerated in many countries because of the implementation of sampling programs for young bulls and improved evaluation procedures. Rapid access to information and more frequent calculation of genetic information also are having a positive impact on genetic improvement. Traits other than yield should be considered in a breeding program, but those traits mist have a reasonable opportunity for improvement and sufficient economic worth. Because of ever increasing efficiency, the world's milk supply comes from fewer cows each year. However, no decline in the rate of genetic improvement is apparent under current genetic practices; estimates of heritability are increasing, and a decline in yield efficiency is unlikely in the near future. As management improves, especially for subtropical conditions, many of the selection principles used in temperate climates will be adopted for more adverse environmental conditions.

• Journal of Animal Science and Technology
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• v.57 no.4
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• pp.13.1-13.5
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• 2015

As an alternative to radioimmunoassay a simple and highly sensitive enzyme immunoassay (EIA) was developed and validated for androstenedione quantification in plasma of Karan Fries bulls using second antibody coating technique. The wells of the microtitreplate were coated with affinity-purified goat immunoglobulin (antirabbit IgG) that binds the hormone specific antibody. The EIA was performed to analyze androstenedione directly in $40{\mu}l$ of bull plasma. The androstenedione standards ranged from 0.20 to 200 pg/$40{\mu}l$/well and the sensitivity of the assay was 5 pg/ml plasma. Serially diluted bull plasma containing high endogenous androstenedione showed good parallelism with bovine androstenedione standard curve. Intra- and inter-assay coefficients of variation (CV) were found to be 8 and 9%, respectively. Peripheral plasma androstenedione concentrations determined in young and adult bull samples ranged between 104-990 pg/ml and 184-2040 pg/ml, respectively.

• Korean Journal of Agricultural Science
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• v.47 no.1
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• pp.43-58
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• 2020

Mulching plastic is used for the purpose of maintaining soil temperature, moisture, and weed and pest prevention in agriculture. Any remaining plastic after use may contaminate the soil and damage crop growth. To solve this problem, mulching plastic wrappers have been studied and developed, but the actual use rate is quite low due to their poor performance and frequent tearing of the plastic on the field. In this study, we developed a tractor attachable mulching plastic wrapper to minimize the tearing of the mulched plastic. The developed mulching plastic wrapper consists of hydraulic motors and pumps, valves, a microcontroller, and sensors. The collecting speed of the plastic mulch was calculated considering the tractor's travel speed and the radius of the collecting drum. A proportional controller was designed to control the rotating speed of the hydraulic motor as the plastic was wound around the collection drum and the radius increased. The performance of an indoor experiment was quite promising because the difference between the collecting speed predicted by the calculation and the actual collecting speed was 2.71 rpm. Based on a field verification test, the speed difference was max. 14.28 rpm; thus, the, proportional integral derivative (PID) controller needs to be considered to control the drum speed precisely. Another issue was found when the soil covered at the edge of the plastic was hardened or the road surface was uneven, the speed control was unstable, and the plastic was torn. In future research, vibrational plows will be equipped to break-up the harden soil for collecting the plastic smoothly.

• Journal of Embryo Transfer
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• v.16 no.1
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• pp.15-27
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• 2001

To identify an antioxidant system, Se and Vit. E were administered into Hanwoo young sire and the effects of administration on blood components(Se, Vit. E, chemical values, estradiol-17 $\beta$, testosterone) were examined. The 16 heads ranging from twenty to thirty two months of age were randomly assigned to control group, Se-administered group(Se-group), Vit. E-administered group(Vit. E-group) and Se and Vit. E administered group(Se and Vit. E-group). Each reagent (Se : 0.1 mg, Vit. E . 1,500IU, Se+vit. E : 0.1 mg+1,500IU per kg of body weight, respectively) administered 3 times every 30days by intramuscular injection. Se concentration in serum was higher in Se-group and Se and Vit. E-group than in control group and Se and Vit. E-group also was higher than Vit. E-group(p<0.05). Although all Se-, Vit. E-administered groups were a little higher than control group, the injection of Se and Vit. E were not significant effect on Vit. E concentration in serum(p>0.05). All groups showed significant variance by periods, but there were not significantly different among groups in blood chemical values. The estradiol-17 $\beta$ concentrations of all Se-, Vit. E-administered groups were a little higher than those of control group, but there were not significant(p>0.05). There have no significant difference among groups in testosterone concentration. These results indicate that the administration of Se, Se + Vit. E increase Se concentration in Hanwoo young bull.

• Korean Journal of Veterinary Research
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• v.40 no.2
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• pp.403-414
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• 2000

To improve the semen production, the selenium(Se) and vitamin E(Vit. E) were administrated into Hanwoo young sire for intensification an antioxidant system and the taurine were supplemented into semen extender for improving the semen characteristics. The 16 heads ranging from twenty to thirty two months of age were randomly assigned to control group, Se-admistrated group(Se-group), Vit. E-administrated group(Vit. E-Group) and Se and Vit. E administrated group(Se and Vit. E-group). Se and Vit. E dministrated 3 times every 30 days by intramuscular injection. The administration of Se, Vit. E, and Se and Vit. E didn't affect on semen volume, sperm concentration, and total sperm number among all groups(p>0.05). Adiministration of Se improved sperm motility and viability. Motility of Se-group and control were 26.01% and 19.20%, respectively(p<0.05). Viability of Se-group(47.07%) was higher than control group(35.73%), Vit. E group(36.55%)(p<0.05). The administration of Se and Vit. E didn't affect sperm capacitation and acrosome reaction. The 100mM taurine supplement into semen extender increased the motility of frozen/thawed semen in the Vit. E-group(p<0.05) and had a beneficial effects on decreasing abnormality of frozen/thawed semen in all groups(p<0.05). These results indicate that Se administration improve sperm motility and viability, and the taurine supplement into semen extender decrease abnormality in Hanwoo young sire.

• Asian-Australasian Journal of Animal Sciences
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• v.26 no.6
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• pp.766-771
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• 2013

The purpose of this study was to investigate interaction effects of genes using a Harvester method. A sample of Korean cattle, Hanwoo (n = 476) was chosen from the National Livestock Research Institute of Korea that were sired by 50 Korean proven bulls. The steers were born between the spring of 1998 and the autumn of 2002 and reared under a progeny-testing program at the Daekwanryeong and Namwon branches of NLRI. The steers were slaughtered at approximately 24 months of age and carcass quality traits were measured. A SNP Harvester method was applied with a support vector machine (SVM) to detect significant SNPs in the CCDC158 gene and interaction effects between the SNPs that were associated with average daily gains, cold carcass weight, longissimus dorsi muscle area, and marbling scores. The statistical significance of the major SNP combinations was evaluated with $x^2$-statistics. The genotype combinations of three SNPs, g.34425+102 A>T(AA), g.4102636T>G(GT), and g.11614-19G>T(GG) had a greater effect than the rest of SNP combinations, e.g. 0.82 vs. 0.75 kg, 343 vs. 314 kg, 80.4 vs $74.7cm^2$, and 7.35 vs. 5.01, for the four respective traits (p<0.001). Also, the estimates were greater compared with single SNPs analyzed (the greatest estimates were 0.76 kg, 320 kg, $75.5cm^2$, and 5.31, respectively). This result suggests that the SNP Harvester method is a good option when multiple SNPs and interaction effects are tested. The significant SNPs could be applied to improve meat quality of Hanwoo via marker-assisted selection.

• Journal of Animal Science and Technology
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• v.47 no.2
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• pp.147-158
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• 2005

The purpose of this study was to find out the effects that daughters' incomplete lactation records affect sire's breeding values through genetic evaluation using RRTDM(random regression test-day model). First, we estimated genetic parameters and breeding values on sires having complete lactation records of daughter by RRTDM, second, we changed complete lactation records of specific sires into incomplete records by various methods. Third, the breeding values were compared between complete and incomplete records. Finally, this study aimed to find out the methods to minimize the estimation errors of young bulls' breeding values. Data used in this study were collected from the dairy herd improvement program, and a total of 97,562 records were composed of 10,929 first parity with both parents known, since 1999. Breeding values on the daughters from randomly chosen sires were calculated and compared with among 90 day, 150day, and 200 day's incomplete records. For milk yields, sire's ranks of breeding values used by complete lactation records were very different from sire's ranks of breeding values obtained by incomplete lactation records(Rank_90 cut, 150cut, 200 cut).The differences were also obtained between complete lactation records(per305_full) and incomplete lactation record (per_90 cut, 150cut, 200 cut) in breeding values regarding persistency. Especially, the differences between per_90 cut and per305_full were very large(from 1.8 kg to 145kg).

• Korean Journal of Veterinary Service
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• v.24 no.1
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• pp.9-14
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• 2001

This study was carried out to investigate the prevalence of Neospora caninum infection in dairy cow and Korean native cattle(KNC), raised in several Chungnam province. To determine the prevalence of antibodies to N caninum, a total of five hundred fifty six sera were analyzed by indirected fluorescent antibody(IFA) test. Five hundred thirty three sera were collected from fifteen dairy herds and twenty three sera were taken from fourteen KNC herds from December 1999 to November 2000. Seropositive ratio of the dairy cattle sera were individually or herdly tested and showed 64.2% and 93.3%, respectively. It was recorded with 78.6% and 47.8% in KNC. The seropositive ratio of dairy cattle was depended on the size of ranch. It was 92.2, 60.7 and 57.9% at the size of less than thirty, thirty to seventy and more than seventy one cattle, respectively However, it was different from the province of Chungnam. The seropositive ratio to N caninum of dairy cattle were 79.5, 53.1, 61.4 and 31.1% at Gongju, Yeongi, Geumsan and Cheongwon, respectively. It showed difference at the growth stage and sex of cattle. The seropositive ratios of N caninum of calf, heifer, premiparous, multiparous(2nd-5th), multiparous (6>th) and bulls confirmed to 25.0, 50.3, 70.3, 71.2, 50.0 and 50.0%, respectively. It was related with brucellosis in cattle. The infected ones with brucellosis were 75.7% of seropositive ratios to N caninum. The results of this study indicated that N caninum infection was widespread in Chungnam province and confirmed existing with brucellosis in cattle.

• 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.