• Journal of Animal Environmental Science
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• v.15 no.1
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• pp.9-16
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• 2009

This study, tasting 14 months, was conducted to investigate the effects of different pen size and group size on growing-fattening characteristics of Hanwoo steers. Forty-eight, 12-month-old Hanwoo steers($305.8{\pm}32.2\;kg$) were randomly assigned to three groups($35.28\;m^2$; n=4 heads, $70.56\;m^2$; n=8 heads, $105.84\;m^2$; n=12 heads) and reared in separate pens with a constant space allowance of $8.82m^2$ per head from 12 to 21 month of age and then regrouped to 4 heads per pen. A common diet including concentrate(limited) and forage(ad lib) was provided to all the animals. Images of live animal ultrasonic back fat thickness, longissimus muscle area and Marbling score were evaluated in three months interval from 12 months of age using an ultrasound equipment(HS-2000) at the 13th rib and lumber vertebra interface of left side. Significant differences of ADG was found mainly at $15{\sim}18$ month and $18{\sim}21$ month fattening stages(p<0.05). Marbling score(MS) was higher(p<0.05) in 12 heads group when compared with that of 4 and 8 heads groups after 18 months. Animals in 12 heads group had the lowest Average daily gain(ADG) but showed the highest longissimus muscle area(LMA) and marbling score(MS). In addition, Hanwoo steers in 12 heads group obtained a higher quality appearance(HQA) of 82.7% than that of other treatments. The results indicated that Hanwoo steers housed on large group size and pen size decreased their ADG but improved meat quality.

• Journal of Animal Environmental Science
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• v.1 no.2
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• pp.145-153
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• 1995

This study was conducted to determine the effects of non-climatic environmental factors on performances and behavioural patterns of growing pigs. Two hundred and seventy growing pigs were confined and administered with three levels of spaces per pig(0.33, 0.44 and 0.66$m^2$) and three different numbers of pigs per pen(12, 15 and 18 pigs) from 30kg to 60kg body weight. This study was designed by using 3 $\times$ 3 factorial arrangement(three levels of spaces $\times$ three different numbers of pigs) and investigated the effects of main factors and the relationship between each factors. The result of this study were summarized as follows; 1. The 0.44$m^2$ of floor space per pig improved(p<0.01) the weight gain and the feed/gain during the growing phase. 2. The 15 pigs per pen showed the faster gain and improved feed/gain than the 12 or 18 pigs per pen during the growing phase(p<0.05). 3. The reduction of floor space of growing pigs caused the reduction of resting, non-aggressive social behaviour but eating, aggressive behaviour was increased(p<0.01). 4. Group size affected the behavioural patterns significantly(p<0.01) of growing pigs. The aggressive and eating behaviour increased but resting behaviour decreased by crowding in the growing pigs. 5. Therefore we concluded that growing pigs need 0.44$m^2$ per pig and 15 pigs per pen for the better raising condition.

• Asian-Australasian Journal of Animal Sciences
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• v.25 no.11
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• pp.1553-1558
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• 2012

This study was conducted to investigate the effects of stocking density or group size on feed intake, daily gain, and carcass characteristics of Hanwoo (Korean indigenous breed) steers reared from 7 months to 31 months of age. Thirty Hanwoo steers were divided into four groups with three replicates each (a total of 12 pens). In each group, one (G1), two (G2), three (G3), and four steers (G4) per pen were allocated as treatments. Pen size was $32.0m^2$, and therefore Hanwoo steers in G1, G2, G3, and G4 were reared under different space allowances, i.e. 32.0, 16.0, 10.6, and $8.0m^2$/steer, respectively. Steers were reared following a conventional beef cattle management method in Korea, and were offered a fixed amount of commercial concentrate with ad libitum forages. Results were subjected to analysis of variance with stocking density as the main effect, and significance was declared at p<0.05. Although total feed intake was not significantly altered, it numerically increased in animals of low stocking density (G1) compared to those subjected to high stocking density treatment (i.e. G4). Feed conversion ratio was higher (p<0.05) in G3 compared to G1 and G2. Animals in G1 (low stocking density) grew faster (p<0.05) than those of high stocking density (G3 and G4). Back fat thickness, meat yield index, and meat yield grade were similar among all levels of stocking density. However, longissimus muscle area was larger in G1 and G2 (p<0.01) compared to G3 and G4, and animals in G3 produced smaller carcasses (p<0.05). Carcass quality traits, including marbling score, meat color, fat color, texture, maturity and meat quality grade, as determined by a group of experts, were not significantly different among the treatments. In conclusion, lower stocking density resulted in increased feed efficiency, daily gain, and carcass weight in Hanwoo steers. However it remains unclear whether such differences are the results of stocking density or group size, or a combination of both. Nonetheless, these results confirm previous studies reporting a negative effect of increased stocking density on animal productivity. Further, animal welfare under an intensive farming system in relation to economical return is discussed.

• The Korean Journal of Malacology
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• v.28 no.4
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• pp.363-375
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• 2012

The gametogenic cycle, the number of spawning seasons per year and first sexual maturiity of the pen shell, Atrina (Servatrina) pectinata, were investigated by quantitative statistical analysis using an Image Analyzer System. Compared two previous results (the spawning periods in the reproductive cycles in 1998 and 2006) by qualitative histological analysis with the present results by quantitative statistical analysis, there are some differences in the spawning periods: the spawning period (June to September) by quantitative statistical analysis was one month longer than those of two previous reports (June to July or June to August) by qualitative histological analysis. However, the number of spawning seasons studied by the qualitative and quatitative analyses occurred once per year. In quantitative statistical analysis using an image analyzer system, the patterns of monthly changes in the percent (%) of the areas occupied by follicles to the ovary area in females (or that of the areas occupied by spermatogenic stages to the testis area in males) showed a maximum in May, and then sharply droped from June to September, 2006. From these data, it is apparent that the spawning season of A. (S.) pectinata occurred once a year from June to September, indicating a unimodal gametogenic cycle during the year. Shell heights of sexually mature pen shells (size at 50% of group sexual maturity, $GM_{50}$) that were fitted to an exponential equation were 15.81 cm in females and 15.72 cm in males (considered to be one year old).

• Journal of Animal Environmental Science
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• v.1 no.2
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• pp.137-144
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• 1995

This experiment was conducted to determine the effects of non-climatic environmental factors on growth performances and behavioural patterns of weanling pigs. Three hundred and sixty weanling pigs were contained and carried out with three levels of spaces per pig(0.18, 0.23 and 0.30$m^2$) and three different numbers of pigs per pen(15, 20 and 25 pigs) up to 30kg body weight. Designed by using a 3 $\times$ 3 factorial arrangement(three levels of spaces $\times$ three different numbers of pigs). This experiment investigated the effects of main factors and the relationship between each factors. The result of this experiment were summarized as follows ; 1. The reduction of floor space caused the reduction of feed/gain in the weanling pigs. Pigs responded with the increased feed intake(p<0.01) and with no change in body weight gain. 2. There were no significant differences in the body weight gain and feed/gain in weanling pigs by changing group sizes, but group size affected the feed intake significantly(p<0.01). 3. Space allowance affected the behavioural patterns significantly(p<0.01) of weanling pigs. The reduction of floor space caused the increment of aggressive behaviour and weanling pigs responded with the decreased resting, non aggressive social and play behaviour. 4. There were no significant differences in the resting, eating, aggressive and non aggressive social behaviour in weanling pigs by changing group sizes, but the large group size caused the reduction of play behaviour in the weanling pigs(p<0.01). 5. Therefore we concluded that weanling pigs require 0.23$m^2$ per pig and 20~25 pigs per pen for the better environment condition.

• Journal of Aquaculture
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• v.11 no.2
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• pp.193-201
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• 1998

This study was carried out to investigate the enviromental quality and the growth of transplanted pen shell, Atrinna pectinata japonica. Followings are the results of growth of transplanted pen shell with respect to the shell size groups from the natural habitat (Usando) in May 1995, and cultivated upto November in the transplantated area (Soomoonri). The water depth of transplantated area andnatural habitat were 3m, 20~25m, respectively. The seawater temperature of the two culturing farms were ranged of 10.9~$27.8^{\circ}C.$, 8.5~$30.0^{\circ}C.$, respectively at the lowest in November adn the highest in July. The seawater salinity of the two areas were ranged of 29.54~35.26$^0\prime\infty$, 28.75~36.31$^0\prime\infty$, respectively at the lowest in July and the highest in November. The phosphoric acid ($PO_4$-P) of the two areas were 0.09~$1.14 ^{\mu}$g-at/l, 0.23~$1.33 ^{\mu}$g-at/l, respectively at the lowest in June and the highest in September. The bottom type of the two areas was a silty mud, 85.23% (82.17~87.26%) in natural habitat and 92.12% (90.76~92.94$^0\prime\infty$) in transplanted area. In this study area, phytoplankton were composed of 19 species. Of these 19 species, Skeletonema costatum was dominant species in seawater between natural habitat and transplantatied area, and 157 cells/ml, 165 cells/ml at August respectively. Stock of phytoplankton in transplantated area were more than those of natural habitat except June and November. The growth of shell length, shell height, total weight, soft part weight and posterior adductor muscle weight of pen shell on different size groups (SL 10, 10~15, 15~20, 20cm) were excellent in shell length of 10cm group, and 99.32%, 107.66%, 871.09%, 951.26% and 1,223.76%, respectively. The survival rate of pen shell was 98.10% in the shell length of 10cm groups, 90.35~94.76% in the others groups. The growth of shell length, total weight, soft part weight and posterior adductor muscle weight of pen shell in transplantated area were more 1.3, 2.6, 2.7 and 4.5 times than those of natural habitat.

• Asian-Australasian Journal of Animal Sciences
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• v.22 no.9
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• pp.1328-1333
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• 2009

To evaluate different housing systems, 80 gilts were randomly allocated at puberty to four treatments: i) sow stall in gestation followed by farrowing crate (SC), ii) group housing with individual feeding in gestation followed by farrowing crate (GC), iii) ESF (Electronic Sow Feeding) system in gestation followed by farrowing crate (EC), and iv) ESF system followed by group farrowing pen (EG). The results showed that stalled sows had a longer interval between puberty and second estrus (p<0.001). The sows kept in the ESF system gained more body weight (p<0.01) and backfat (p<0.05) prior to service, and more backfat during gestation (p<0.05), but also had greater backfat losses in the subsequent lactation (p<0.01). Sows changing from loose housing to confinement at farrowing had longer gestation length (p<0.001). Total litter size did not differ significantly between gestation treatments, but the number of stillborn piglets was significantly higher in the SC treatment (p<0.01). After weaning, SC sows had the longest interval for rebreeding (p<0.001). Some EG sows came into heat before weaning, giving this treatment the shortest interval. These results indicate that gestation confinement in sow stalls had several detrimental effects on sow performance relative to group housing.

• Korean Journal of Agricultural Science
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• v.43 no.4
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• pp.595-602
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• 2016

In pigs, individuals in the same pen may show aggressive behavior toward each other, such as tail biting. Such social interactions among pen mates may considerably affect their welfare and performance, both in negative and positive ways. The present study was conducted to investigate social genetic effects on days to 90 kg using data from 12,208 Duroc and Yorkshire pigs that were born between 2008 and 2012. Heritability was estimated using the five following animal models: a basic model with direct heritable effects only (Model 1), a social model with direct and social heritable effects (Model 2), a model accounting for covariance between direct and social heritable effects (Model 3), and two models considering a dilution factor with direct and social heritable effects (Models 4 and 5). The optimal model to represent Duroc pigs was Model 1 which only uses direct heritable effects. Direct heritability (0.21) was higher than total heritability (0.09) and covariance was negative. Model 2 was evaluated as the optimum model for Yorkshire pigs. Yorkshire data showed that total heritability (0.5) was twice as high as direct heritability (0.25) and covariance was positive. Our results suggest that the efficiency of social effects differed among breeding lines. Further research on social effects related to breeds by group size would clarify which is the most efficient selection method that accounts for social genetic effects.

• Polymer(Korea)
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• v.26 no.4
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• pp.422-430
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• 2002

The kinetics of polycondensation of bishydroxyethyl naphthalate has been studied in the range of 241 -$260^{\circ}C$ using antimony trioxide catalyst. The reaction was performed in a batch reactor and the concentration of reaction mixture was measured with HPLC. The activation energy values of forward and reverse reaction determined from molecular species model were found to be 19.7 and 31.4 kcal/mole, respectively, and the equilibrium constants were in the range of 1.4-2.0, which were larger than that of polycondensation of PET and varied to some degree with temperature. It was confirmed by applying the Flory's distribution function that the reaction rate of the hyroxyethyl group does not depend on the molecular size. By applying functional group model, we observed that there was few difference between the activation energy of the forward reaction and that of reverse reaction, therefore the equilibrium constant has almost constant value of 1.4. The rate constants obtained from functional group model was about 3-4 times larger than that from molecular species model, which showed that both model explains the reaction system well. Although the molecular species model should predict the concentration of as many as ten molecules, it fits for the experimental results well.

• Journal of Elementary Mathematics Education in Korea
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• v.18 no.3
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• pp.459-474
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• 2014

The purpose of this study was to investigate the effects of mathematical instruction using GSP program on the symmetrical figures learning and self-directed learning attitude. According to the pretest result, the experiment group and the comparison group showed to be homogeneous groups. The experiment group has learned symmetrical figures for 9 hours using the GSP program and the comparison group has learned for 9 hours using the traditional method(paper and pen lesson). As the posttests, self-directed learning attitude test and symmetry figure understanding test were performed. The results obtained in this research are as follows; First, there was a significant difference in symmetry figure understanding test between the experiment group which learned through GSP program and the comparison group which learned through traditional method. Since there showed a very high achievement in the experiment group which learned using GSP, it can be inferred that GSP was very effective in the lessons of symmetrical movements. Second, there was a significant difference in self-directed learning attitude test between the experiment group and the comparison group. This seems to be because the length of the sides of the figures, size of the angles of the figures etc can be verified instantly and the students can correct by themselves and give feedbacks when they use GSP program. Students preferred drawing using the GSP over drawing using rulers and pencils, and they showed interest in the GSP program and they did not have burden in being wrong in their study and studied in various methods. And as they become familiar with the GSP program, they even studied other contents beyond the scope presented in the textbook.