• Asian-Australasian Journal of Animal Sciences
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• v.23 no.7
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• pp.873-879
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• 2010

We investigated the effect of various concentrations of taurine during in vitro fertilization (IVF) on the embryonic development up to the blastocyst stage of bovine oocytes fertilized with three different Japanese Black bulls (Bull A, B and C). In vitro matured oocytes were fertilized with various concentrations of taurine (0, 1, 10, 50 and 100 mM) in the presence of 2.5 or 5.0 mM caffeine plus $25{\mu}g$/ml heparin (CH) for 6 hr or $100{\mu}g$/ml heparin (H) for $24{\pm}2$ h. After IVF, the cleavage rates from the 2 to 16 cell stage determined at 3 days and the development rates up to the blastocyst stage determined at 7-8 days from the onset of IVF were assessed. Although the cleavage rates for the taurine concentration groups were not significantly increased in any of the three bulls in the CH groups, the development rates up to the blastocyst stage of the 50 mM taurine group of Bulls A and B, and of the 1 to 50 mM groups of Bull C were increased (p<0.05) compared to those of the control (0 mM taurine) groups. On the other hand, none of the bulls in the H groups showed any significant increase either in the cleavage rates or blastocyst formation rates in any taurine concentrations groups compared with those of the control groups. These results indicate that the addition of 50 mM taurine to a fertilization medium containing caffeine and heparin may stimulate embryonic development up to the blastocyst stage when fertilized with different bull semen.

• Asian-Australasian Journal of Animal Sciences
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• v.21 no.12
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• pp.1807-1814
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• 2008

This study was carried out to investigate the effects of housing system on the carcass and meat qualities of Hanwoo (Korean cattle) bulls. Fourteen 6 months-old male calves were randomly divided into two groups. The first group was individually tethered using double neck-bar tethers. The second group was collectively loose-housed in the pen. They were raised for 15 months prior to slaughter. At 24 h post-slaughter chilling, the carcasses were weighed and evaluated by official grader for carcass traits. At 48 h post-slaughter chilling, the M. longissimus at the $12-13^{th}$ thoracic vertebra from each carcass was collected and stored at $4{\pm}0.2^{\circ}C$ for 7 days for meat quality analysis. There were no significant differences in dressing percentage and carcass yield index between groups. Meat from loose bulls had lower marbling score (p<0.05) and fat content (p<0.01) but higher PUFA concentration (p<0.001) than that from tethered bulls. There were no significant differences physical and sensory properties, aroma pattern, TBARS value, metmyoglobin concentration and CIE color values during refrigerated storage between groups. Compared to tethering, loose-housing bulls produced lower fat content and healthier meat without different physical properties, acceptability, and lipid and color stabilities.

• Asian-Australasian Journal of Animal Sciences
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• v.8 no.6
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• pp.611-616
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• 1995

A study was conducted which demonstrated that Dhofari cattle responded well to intensive management systems in terms of growth rates and carcass yields. Twenty-four Omani Dhofari bulls and steers (12 of each) were reared from birth until slaughter at 110, 160 and 210 kg body weight (for of each sex at each slaughter weight). Calves were fed ad libitum a diet of concentrate (16.5% CP) and Rhodesgrass hay (8.8% CP). Bulls and steers reached the predetermined slaughter weights of 110, 160 and 210 kg at 154 and 164; 219 and 233; 273 and 310 days of age, respectively. Respective mean pre and post-weaning daily body weight gains for bulls and steers were 581 and 530; 796 and 706 g averaging 645 and 596 g over 36 weeks. At 210 kg, the heaviest weight of the study, dressing-out percentage (DO) was 54.5 and 56.9 yielding carcasses of 115.9 and 118.5 kg which contained 60.4 and 61.5% muscle; 11.6 and 11.4% bone and 24.5 and 22.9% fat for bulls and steers, respectively. Proportion of bone in the carcass decreased, that of fat increased, whereas that of muscle remained unchanged between slaughter weights of 110 to 210 kg. That resulted in increased muscle : bone and decreased muscle : fat ratios. At 160 kg body weight, bulls had less fat and more muscle and bone than steers but there were no sex differences in carcass composition at 210 kg slaughter weight.

• Asian-Australasian Journal of Animal Sciences
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• v.28 no.1
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• pp.127-134
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• 2015

Castration induces the accumulation of body fat and deposition of intramuscular fat in Korean cattle, resulting in improved beef quality. However, little is known about the metabolic adaptations in the liver following castration. To understand changes in lipid metabolism following castration, hepatic expression levels of lipid metabolism genes were compared between Korean bulls and steers. Steers had higher (p<0.001) hepatic lipids contents and higher (p<0.01) mRNA levels of lipogenic acetyl-CoA carboxylase. This differential gene expression may, in part, contribute to increased hepatic lipid content following the castration of bulls. However, we found no differences in the hepatic expression levels of genes related to triglyceride synthesis (mitochondrial glycerol-3-phosphate acyltransferase, diacylglycerol O-acyltransferase 1 and 2) and fatty acid (FA) oxidation (carnitine palmitoyltransferase 1A, C-4 to C-12 straight chain acyl-CoA dehydrogenase, very long chain acyl-CoA dehydrogenase) between bulls and steers. No differences in gene expression for very-low-density lipoprotein (VLDL) secretion, including apolipoprotein B mRNA and microsomal triglyceride transfer protein (MTTP) protein, were observed in the liver although MTTP mRNA levels were higher in steers compared to bulls. In conclusion, FA synthesis may contribute to increased hepatic lipid deposition in steers following castration. However, hepatic lipid metabolism, including triglyceride synthesis, FA oxidation, and VLDL secretion, was not significantly altered by castration. Our results suggest that hepatic lipid metabolism does not significantly contribute to increased body fat deposition in steers following castration.

• Asian-Australasian Journal of Animal Sciences
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• v.27 no.10
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• pp.1452-1460
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• 2014

The objective of this work was to evaluate the nutritional parameters of young bulls supplemented with different ratios of protein: carbohydrate on tropical pastures from 4 until 18 months old. Fifty-five non-castrated beef calves ($138.3{\pm}3.4kg$, 90 to 150 d of age) were used. The calves (young bulls) were subjected to a 430-d experimental period encompassing 4 seasons. The treatments were as follows: control, only mineral mixture; HPHC, high protein and high carbohydrate supplement; HPLC, high protein and low carbohydrate supplement; LPHC, low protein and high carbohydrate supplement; and LPLC, low protein and low carbohydrate supplement. The amount of supplement was adjusted every 28 d. Dry matter (DM) intake was higher in the dry-to-rainy transition and rainy seasons for all nutritional plans. Non-supplemented animals had lower intakes of DM and total digestible nutrients (TDN) than supplemented young bulls in all seasons. Although differences in DM intake were not observed between supplemented animals, the supplements with high carbohydrate (HPHC and LPHC) had lower forage intake during suckling (rainy-to-dry transition season) and in the rainy season. However, the HPHC treatment animals had higher intake and digestibility of neutral detergent fiber. It can be concluded that supplementation with high protein levels (supplying 50% of the crude protein requirement) provide the best nutritional parameters for grazing young bulls in most seasons, increasing intake and digestibility of diet, and these effects are more intense when associated with high carbohydrate levels level (supplying 30% TDN requirement).

• Asian-Australasian Journal of Animal Sciences
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• v.32 no.2
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• pp.159-169
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• 2019

Objective: Models for genomic selection assume that the reference population is an unselected population. However, in practice, genotyped individuals, such as progeny-tested bulls, are highly selected, and the reference population is created after preselection. In dairy cattle, the intensity of selection is higher in males than in females, suggesting that cows can be added to the reference population with less bias and loss of accuracy. The objective is to develop formulas applied to any genomic prediction studies or practice with preselected animals as reference population. Methods: We developed formulas for calculating the reliability and bias of genomically enhanced breeding values (GEBV) in the reference population where individuals are preselected on estimated breeding values. Based on the formulas presented, deterministic simulation was conducted by varying heritability, preselection percentage, and the reference population size. Results: The number of bulls equal to a cow regarding the reliability of GEBV was expressed through a simple formula for the reference population consisting of preselected animals. The bull population was vastly superior to the cow population regarding the reliability of GEBV for low-heritability traits. However, the superiority of reliability from the bull reference population over the cow population decreased as heritability increased. Bias was greater for bulls than cows. Bias and reduction in reliability of GEBV due to preselection was alleviated by expanding reference population. Conclusion: Cows are easier in expanding reference population size compared with bulls and alleviate bias and reduction in reliability of GEBV of bulls which are highly preselected than cows by expanding the cow reference population.

• Food Science of Animal Resources
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• v.31 no.2
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• pp.257-265
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• 2011

The current study was conducted to compare the growth performance and physico-chemical characteristics of Hanwoo bulls and steers of different slaughtering ages. Thirty-six Hanwoo (average age, 13-mon) were allocated into either a bull or steer group (18 animals/group). Each group was sub-divided into 26-, 28-, and 30-mon-old age groups (six animals/group). Surgical castration was performed in the steer group immediately after the experimental groups were assigned. Growth performance of the animals, as well as carcass characteristics and fatty acid composition of M. longissimus dorsi were determined. Cold carcass weights increased as carcass slaughtering age increased in both Hanwoo bulls and steers (p<0.05). Backfat thickness was thickest (p<0.05) in 28-mon-old Hanwoo bulls and 30-mon-old steer, and the M. longissimus dorsi area was widest (p< 0.05) in 28-mon-old Hanwoo bulls and steers. Marbling score, cooking loss, and water holding capacity (WHC) were higher (p<0.05) in 30-mon-old Hanwoo bulls and steers as slaughtering age increased. The shear force value was highest in 30-mon-old Hanwoo bulls and 26-mon-old Hanwoo steers compared to that in other groups. The unsaturated fatty acid composition in M. longissimus dorsi was significantly (p<0.05) higher in 28- and 30-mon-old Hanwoo bulls and steers than that in other groups. The results suggest that castration, even at late stages of Hanwoo development, improved beef carcass quality grade, and that no difference in beef quality grade had occurred (marbling score and WHC) in 28- and 30-mon-old slaughtering age Hanwoo steers.

• Korean Journal of Organic Agriculture
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• v.24 no.4
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• pp.931-944
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• 2016

This study was conducted to compare among bull, steer and heifer on growth performance, blood composition and carcass traits according to fattening phase in Hanwoo. 12 month of aged 4 bulls ($339.8{\pm}18.5kg$), 4 steers ($309.8{\pm}13.2kg$), and 3 heifers ($290.0{\pm}16.7kg$) were allocated in the stalls with individual feeding system during 20 months. Average daily gain was not different among the treatment groups during early fattening phase, but higher in the bulls and lower in the heifers after mid-fattening phase (p<0.05). The difference of body size by animal groups appeared from 24 month of age, and wither height and body length of Hanwoo heifer were the smallest (p<0.05) among treatment group. But wither height was not difference among treatment groups at 32 month of age. At 12 month of age, concentrations of serum cholesterol, triglyceride, glucose and total protein were higher in the heifers compared to other groups, and serum GPT (Glutamic pyruvic transaminase) was the highest (p<0.05) in the bulls, and serum GOT (Glutamic oxaloacetic transaminase) was the highest (p<0.05) at late fattening phase in the bulls. Meat yield index was similar between the bulls and the heifers, and the lowest (p<0.05) in the steers. Marbling score was significantly higher (p<0.05) in the steers and the heifers than in the bulls, and meat quality was the best in the steers among treatment groups. The results of this experiment might be used as a basal data on difference between gender in revision of Korean feeding standard for Hanwoo.

• Asian-Australasian Journal of Animal Sciences
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• v.19 no.5
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• pp.705-712
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• 2006

Influences of urea treated corncobs (UTC) ensiled with or without different additives on ruminal characteristics, in situ digestion kinetics, nutrient digestibility and nitrogen metabolism were examined in a $5{\times}5$ Latin square design using five ruminally cannulated buffalo bulls. Five iso-caloric and iso-nitrogenous diets were formulated to contain 30% dry matter (DM) from concentrate and 70% DM from 5% UTC ensiled without any additive (U) or with 5% enzose (EN), 5% acidified molasses (AM), 5% non-acidified molasses (NM) and 5% acidified water (AW), respectively. These diets were fed to buffalo bulls at 1.5% of their body weight daily. Ruminal $NH_3$-N concentration at 3 hours (h) post feeding was significantly higher in bulls fed U, NM and AW diets, however, at 6, 9 and 12 h post feeding it was significantly higher in bulls fed EN and AM diets. Ruminal total volatile fatty acids (VFA) and acetate concentrations were significantly higher with EM and AM diets compared with other diets at 3, 6, 9 and 12 h post feeding. Ruminal pH at 6 and 9 h post feeding was higher with EN and AM diets; however; it was notably lower with these diets at 3 h post feeding. Total ruminal bacterial and cellulolytic bacterial counts were higher in bulls fed EN and AM diets than in those fed the other diets. In situ ruminal DM and NDF degradabilities and total tract digestibilities were significantly higher with UTC ensiled with enzose and acidified molasses than those ensiled without any additive or other additives. Nitrogen balance was significantly higher in bulls fed EN and AM diets than those fed U, AW and NM diets. The UTC ensiled with enzose or acidified molasses resulted in better digestibility and N utilization than those ensiled without any additive, with non-acidified molasses and acidified water in buffaloes.

• Korean Journal of Veterinary Service
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• v.20 no.1
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• pp.1-9
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• 1997

The 37,000 holstein which had been raised in Jeju island were examined for the purpose of brucellosis detection and so on. We investigated the relationship between the farms showing positive outbreak and the number of examination, incubation period, and the outbreak rate of positive cattle. We endeavored to separate germs from brucellosis positive cattles blood and negative bulls semen against brucellosis serum test and concluded as follows. We intend to offer you institutional supplements and preventions of brucellosis for the future. 1. Outbreak of brucellosis could not lead the outbreak rate of positive cattle to decrease through 1-2 examination per year, For the past 4 years, the outbreak rate of brucellosis positive cattle had a tendency to show a gradual decrease through at least 5 examinations per year. 2. As we examined live-in cattle with positive cattle in mass outbreak farms for 9 months, we found out positive cattle every month. In a grazing land, the group of cattle producd enormous positive cattle in 9-12 months. 3. Annual brucellosis positive outbreak rate was 20-25% among live-in cattle with brucellosis positive cattle, but the rate might be 50-100% depending on extent of pollution. 4. 94's brucellosis examination showed that 200 positive cattle of 71,153 cattle and most of them were live-in cattle with confirmed brucellosis positive cattle. 5. 1 head of 200 positive cattle showed positivity against serum of bulls test and the rate of bulls was about 1%. 6. Brucellosis germ was separated from 2 cattle's semen among 52 negative bulls against brucellosis serum test and there was the one brucellosis positive cattle against tube agglutination of semen test, so the positive rate of brucellosis was 5.8%. 7. Brucellosis germ was not separated from 15 brucellosis positive cattle's blood.