• Korean Journal of Veterinary Service
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• v.47 no.2
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• pp.81-87
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• 2024

From July to December 2022, we investigated the incidence of enteric pathogens causing diarrhea in calves under 100 days old at 22 farms across Korea. A total of 354 calves (including 247 dairy calves and 107 Korean native calves) were included. We used commercially available rapid diagnostic kits to identify five enteric pathogens, including bovine rotavirus (BRV), bovine coronavirus (BCoV), Cryptosporidium. Escherichia coli (E. coli), and Giardia. This study investigated how factors such as age, season, and birth month, which can influence the incidence of intestinal pathogens, affect the incidence of these pathogens in diarrheic dairy calves and Korean native calves. Our study found that the incidence of diarrhea-causing pathogens differed between dairy and Korean native calves. In diarrheic dairy calves, bovine rotavirus (BRV) incidence rates, correlated with season and birth month. Similarly, Cryptosporidium incidence C were associated with age and season, while Giardia incidence rates varied by season and birth month. Korean native calves, on the other hand, exhibited seasonal and birth month-related variations in BRV incidence rates, with Cryptosporidium incidence rates influenced by birth month.

• Korean Journal of Ichthyology
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• v.33 no.1
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• pp.31-36
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• 2021

In order to understand the age and growth characteristics of Pacific anchovy, Engraulis japonicus, the 506 otoliths of individuals collected in the southern waters of Korea in 2004 were analyzed. Monthly age of anchovies was estimated based on the age determined through the year rings and their collection date. The growth parameters obtained using the monthly folk lengths were a theoretical maximum body length of 132.9 mm, a growth coefficient of 0.1079/month and a theoretical age of 0.0262 month when the fork length is zero. The growth equation of von Bertalanffy presented by the growth parameters was L_t=132.9(1-e^{-0.1079(t-1.0262)}). The estimation of growth parameters based on the monthly age established through year ring and collection date was deemed appropriate for understanding the growth characteristics of anchovies.

• Pediatric Gastroenterology, Hepatology & Nutrition
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• v.16 no.4
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• pp.240-247
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• 2013

Purpose: Regurgitation is known to peak at the age of 3-4 months, with a sharp decrease around the age of 6 months. Little is known about the natural evolution of infants who still regurgitate after the age of 6 months. Methods: Hundred thirty-one infants older than 6 months regurgitating more than once a day were followed for a period of 3 months. Results: According to our data, gastroesophageal reflux disease (GERD) is seldom at this age. Most of the infants regurgitated 3 or more times/day and spit up an estimated volume of more than 15 mL. Eighty-five parents were educated regarding frequency of feeding. There were only 6 infants that still had frequent regurgitation (>3 times/day) despite an appropriate feeding schedule. The Infant GER Questionnaire score reached a score of 0 in 50% of the infants after one month of follow-up and in 81.9% at the third month of follow-up. There was an increase of the "weight for age z-score" trends in infants that still regurgitated at the end of follow-up and a declining z-score in infants that no longer regurgitated. An explanation may be that infants that regurgitate drink larger volumes than infants who do not regurgitate. Conservative treatment (reassurance, dietary treatment, behavioral advice) resulted in a significant better outcome than natural evolution. Conclusion: Regurgitation that persisted after the age of 6 months, strongly decreased during a 3-month follow-up with conservative treatment. GERD is rare in this age group; therefore, anti-reflux medication is only seldom needed.

• Journal of Animal Science and Technology
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• v.58 no.2
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• pp.8.1-8.14
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• 2016

In this research data representing 72,946 primiparous cows from 724 herds with 638,063 total test day records calved between 2001 and 2011. These data were analysed to determine the effect of age at first and season of calving on parameters of the Wood lactation curve. Also, genetic trend of the lactation curve parameters in different calving years were evaluated. The results indicate that the highest rate of atypical lactation curve was related to cows that calved in summer (28.05 %). The maximum phenotypic relationship between initial milk yield and total 305-d milk yield was observed in cows calved in spring (0.40). The role of peak yield is more than peak time on 305-d total milk yield in primiparous Holstein. One month increase in age at first calving from 18 to 26 month raised 305-d milk yield by around 138 kg and from 27 to 32 month decreased by 61 kg. The persistency of lactation between 101 and 200 days is higher than that of 201-305 days. Our results indicate that the shape of lactation curve is largely dependent on the season of calving (higher level of milk production in cows which calved in autumn and winter). The heritabilities of parameters of lactation curve and persistency measures were low. The genetic trends for peak time, peak yield and 305-d milk yields were positive and estimated to be 0.019, 0.021 and 8.13 kg/year respectively. So the range from 24 to 26.5 month of calving is the optimum calving time in primiparous Holstein for maximizing 305-d milk yield.

• Korean Journal of Veterinary Research
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• v.12 no.1
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• pp.121-126
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• 1972

The pneumonic lungs of 51 pigs, from which the presence of pasteurella organisms was confirmed by bipolar staining, were examined pathologically. The numbers of pigs in each age group were 22 (43.1%) in 3-4 month group, 20 (39.2%) in 1-2 month group, 7 (13.7%) in 5-6 month group, and 2 (4.0%) in group of more than one year. The lungs of 16 pigs which were regarded as pasteurella pneumonia without any other manifestations were studied pathogically. Grossly, the affected lungs showed pulmonary edema, lobular consolidation and interlobular edema. Pigs over 3 months of age frequently showed chronic condition in which the entire lobe was involved as confluent pneumonia. In such pneumonic lungs, infarction and focal necrosis of the lung parenchyma and deposition of fibrinous exudate on the pleura were encountered. Histologically, the alveolar spaces were filled with fibrinous and leukocytic exudates. The interlobular septae showed marked edema and fibrinous exudate. The process of organization was frequently observed in chronic cases.

• Applied Microscopy
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• v.25 no.4
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• pp.26-51
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• 1995

The present study was designed to examine effect of long term weight-training on aging atrophy in the rat skeletal muscle. Male rats of 8, 15, and 24 month old were used. Each age groups included control and weight-training for 5 months by using body press apparatus. The histo- and cytochemical, ultrastructural and stereological changes in aging skeletal muscles of the rat were observed in the present study. During the training period the body weight and muscular weight in all groups except the rectus femoris and the gastrocnemius in young age groups remained constant, but muscular weights were increased in the rectus femoris and the gastrocnemius muscles in young age groups. In trained rat, the volume density of muscle fiber type IIA and IIB were increased, but those of type IIC was decreased. Type I remained constant in 8 and 15 month old age groups, but reduced in the tibialis anterior and the gastrocnemius muscles in the 24 month old groups. Some histotological and ultrastructural changes associated with age were found: numerical increase of cytiplasmic vacuoles, lysosomes, lipofuscins, and irregularity of myofibrils. At 24 month old groups some unusual formation of contraction band and muscle splitting were observed. After weight-training, ultrastructural degenerative changes occured in the type I muscle fiber, such as splitting of muscle fiber, disorganization of myofilaments, swelling of mitochondria, accumulation of many lipid droplets, appearance of many lysosomes and residual bodies and necrotic fibers, in the old age groups. But, in the type II muscle fibers hypertrophy of muscle fiber appeared without any noticible damage as the type I. The activities of $Mg^{++}$ -ATPase decreased with age and this enzyme activities in the trained rat were significantly decreased with age. Activities of the acid phosphatase were increased with age and significantly in the trained rat. In stereological analysis, volume density of the myofibrils and the tubular system were increased, on the other hand there mitochondrial capacity was decreased. These experimental results suggested that old rats are not susceptible to be affected by weight-training as young rats, and that physical capacity of the rats must be considered when old rats are exercised for training.

• Korean Journal of Veterinary Research
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• v.14 no.1
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• pp.115-133
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• 1974

Although considerable research has been done on the changes associated with age in the blood picture of domestic and laboratory animals, little work has been made of the changes occurring at different age in the blood picture of goats. And a comprehensive survey of the bood picture of Korean native goats has not been made. The object of the present investigation was to suggest standards for the blood picture of Korean native goats at frequent intervals from birth to maturity. The goats were kept under average farming conditions in this country. Observations were made at the following ages: at birth; 2,4 and 7 days; 2, 3, 4, 5, 6, 7, 8 and 9 weeks; 2.5, 3,6 and 12 months. Blood samples were drawn from the jugular vein. It was taken between 8 and 9 a.m. except those for the at-birth period. Erythrocyte and leukocyte enumerations and, determinations of hemoglobin in blood and hematocrit value were made in the usual manner. Reticulocytes were enumerated per 1,000 erythrocytes in blood smears stained with briIliant cresyl blue and counterstained with Wright's stain. Erythrocytes counts declined from $8.7{\times}10^8/mm^3$ at birth to a low of 7.0 at 4 days of age. These values increased to 11.5 at 5 weeks and reached a maximum of 14.0 at 3 months of age; it then fell to 11.5 at 12 months of age. Concentrations of hemoglobin in blood and hematocrit values were not related to the changes of erythrocyte counts. The values at birth were higher than at any other period during the first year of life. These fell from highs of 12.3 g/100 ml and 38.0 ml/100 ml to lows of 9.2 and 29 at 4 weeks for concentration of hemoglobin in blood and hematocrit value, respectively. There was a common pattern for the hematocrit value and hemoglobin in blood which showed three phases-a fall during the first month, a rise to the third month, and a fall to the mature level at 12 months of age. Mean corpuscular volume and mean corpuscular hemoglobin showed a common pattern. The values were $44.2{\mu}m^3$ and 14.2 pg at birth and fell, at first slowly and then rapidly, to reach adult levels of 24.1 and 7.9 at 6 weeks of age for mean corpuscular volume and mean corpuscular hemoglobin, respectively. Mean corpuscular hemoglobin concentration was little affected by age. Reticulocyte was observed from birth to 4 weeks of age. Percentage of reticulocyte decreased from 0.85% at birth to 0.06% at 4 weeks of age. Total leucocyte counts increased from $5.64{\times}10^3/mm^3$ at birth to a maximum of 13.4 at 3 months; it then fell to 11.5 at 12 months of age. In differential counts myelocyte, juvenile and band form decreased with advancing age. No myelocyte and juvenile were seen after the age of 7 and 9 weeks, respectively, and band forms were rare after the age of 3 months. Percentage of mature neutrophil showed a quick decline from 52.5% at birth to reach a minimum level (34.5%) at 3 months of age; it then rose to 38% at 12 months of age. Percentage of lymphocyte increased from 39.2% at birth to maximum of 59% at 3 month of age; it then fell to 54.9% at 12 months of age. Percentage of monocyte was not affected with advance of age. Percentage of eosinophil and basophil were increased with advance of age to reach a maximum at 2 to 3 month of age. It then fell to adult level at 12 month of age.

• Clinical and Experimental Pediatrics
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• v.57 no.1
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• pp.41-45
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• 2014

Purpose: Renal size is an important indicator to determine adequate organ growth in children. The aim of this study was to estimate renal size with Technesium-99m dimercaptosuccinic acid (DMSA) scan and propose a simple formula for predicting renal length in normal Korean children. Methods: This study included 346 children (148 boys and 198 girls; age range, 1 month to 17 years) in whom renal length was measured using the DMSA scan. Patients with anatomical renal abnormalities or acute pyelonephritis were excluded. Children were divided into two groups: 214 children (61.8%) were less than a year old (group 1) and 132 (38.2%) were ${\geq}1$ year (group 2). Results: Renal length was larger on the left side than the right side, and there was no significant gender-related difference in renal length. We propose the following formula for renal length based on the analysis of the 346 children in our study: the formula was as follows: $4.682{\times}age(month)^{0.137}$, $R^2=0.780$. In group 1, the formula was renal length $(cm)=0.127{\times}age(month)+5.144$, $R^2=0.354$, and in group 2, the formula was $0.334{\times}age(year)+6.477$, $R^2=0.829$. Conclusion: It is difficult to establish simple formulae in infants ($R^2=0.354$). Therefore, further studies including relevant variables are needed for this age group. We proposed formulae to estimate renal length in Korean children over 1 year of age by using the DMSA scan.

• Reproductive and Developmental Biology
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• v.33 no.4
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• pp.211-216
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• 2009

A cell frequently utilizes glucose as a fuel of energy and a major substrate of lipid and protein syntheses. A regulation of glucose movement into and out of the cells is precisely controlled by cooperative works of passive and sodium-dependent active processes. At least 13 glucose cotransporter (Slc2a, GLUT) isoforms involve in passive movement of glucose in cells. The efferent ductules (EDs) play in a number of important functions for maintenance of male fertility. In the present study, using real-time PCR analysis, we determined gene expression of five Slc2a isoforms in the EDs. In addition, we compared expression levels of these Slc2a isoforms according to postnatal development ages, 1 week, 2 weeks, 1 month, and 3 months. Results from the current study showed that expression of Slc2a1, Slc2a3, and Slc2a5 mRNAs reached the highest levels at 1 month of age, followed by a transient decrease at 3 months of age. In addition, the level of Slc2a4 mRNA reminded at steady until 1 month of age and was significantly reduced at 3 months of age, whereas the highest level of Slc2a 8 mRNA was detected at 2 weeks of age. Data from the present study indicate a differential expression of various Slc2a isoforms in the ED according to postnatal ages. Thus, it is believed that glucose movement through the epithelial cells in the ED would be regulated by the coordinated manner among Slc2a isoforms expressed at a given age.

• Animal cells and systems
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• v.3 no.3
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• pp.269-273
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• 1999

The distribution and relative frequency of somatostatin-immunoreactive cells in the pancreas were studied during developmental stages (fetus, neonate, 1-month-old, 6-month-old and adult) of the Korean native goat by immunohistochemical methods. Somatostatin-immunoreactive cells were detected in the exocrine of all ages, in the endocrine portions (pancreatic islets) from the neonate, and in the pancreatic duct of the 1-month-old. The relative frequencies of these cells in the pancreatic islets increased with age. However, there were no age-related changes in the relative frequencies of somatostatin-immunoreactive cells in the exocrine and pancreatic duct. Generally, they were distributed in the interacinar spaces, the epithelium of the pancreatic duct, or dispersed in the peripheral zone of the pancreatic islets in all ages. However, clusters consisting of 3-4 cells were also found in the subepithelial connective tissues from the 1-month-old. In addition, the distributions in the endocrine portions of the adult were divided into two patterns: 1) they are dispersed in the marginal regions with moderate or low frequencies, or 2) in the inner zone with high frequencies.