• Asian-Australasian Journal of Animal Sciences
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• 제20권2호
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• pp.252-256
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• 2007

This study was carried out to determine the effect of vitamin E and vitamin C on the performance of Japanese quails (Coturnix coturnix japonica) reared under heat stress during the growth and egg production period. A total of 810 seven-day-old Japanese quails were used in the trial. The birds received a diet with either three levels of vitamin E (DL-${\alpha}$Tocopheryl acetate) (60, 120 and 240 mg/kg of diet) and vitamin C (ROVIMIX STAY-C 35) (60, 120 and 240 mg/kg of diet). Live weight on day 35 and weight gain were the lowest in the group of chicks on a combination of 60 mg of vitamin E and 60 mg of vitamin C, whereas the highest live weight was demonstrated in chicks on a combination of 240 mg of vitamin E and 240 mg of vitamin C (p<0.01). The effects of treatments on cumulative feed consumption, feed conversion ratio, age at 5% lay, sexual maturity weight, rate of lay and mean egg weight values were found to be significant (p<0.01). The highest feed consumption, feed conversion ratio, age at 5% lay, sexual maturity weight, rate of lay and mean egg weight values were found in the group on a combination of 240 mg of vitamin E and 240 mg of vitamin C. The effect of treatments on the mortality ratio was found to be insignificant (p>0.01). The cost of supplementing diets with vitamin E and vitamin C is very low. Therefore such a combination of supplement can offer a potential protective management practice in preventing heat stress related losses in performance of Japanese quails.

• 농업과학연구
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• 제46권4호
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• pp.991-997
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• 2019

This study was conducted to investigate the laying period performance of two crossbred Korean native chicken (KNC) grand parent stock (GPS) layer during 20 to 40 weeks. A total of 351 20-week-old KNC GPS were allocated in a completely randomized design to give 4 birds per each cage. The chickens were fed commercial diets [i.e., week 20 - 32, crude protein (CP) 18.0% and metabolizable energy (ME) 2,850 kcal/kg; week 32 - 40, CP 17.0% and ME 2,800 kcal/kg)] and fresh water during the whole experiment period ad libitum basis. Body weight, age of sexual maturity, egg weight, hen-day egg production (HDP) and feed conversion ratio (FCR) were measured during the experiment period (week 20 - 40). The results show no significant difference in the Body weight, age of sexual maturity, egg weight, and hen-day egg production (HDP) except for egg weight. 1B had a higher egg weight on week 36 only. We expect that the reason why most factors showed no significant difference is the lack of nutrients caused by limited feeding which follows the standard feeding system for the grand-parent stock. These results provide basic information for laying data in 2-way crossbred Korean native chickens.

• 한국가금학회지
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• 제17권4호
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• pp.281-283
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• 1990

10주령 병아리를 이용하여 Cage당 10수로 하여 15반복의 시험구를 배치하였다. 10주령까지는 19％의 단백질사료로 사육되었으며 그 후에는 12％의 단백질사료를 이용하여 사육하였다. 대조구는 옥수수와 대두박구로 하고 시험구는 대조구의 대두박 대신 해바라기 씨앗으로 일부(19％) 또는 전부(38％)를 대치하여 19주령까지 사육하였다. 19주령에서 산란계용 cage로 옮긴 후 13.5％의 단백질 수준을 유지시켰다. 시험결과에 의하면 해바라기씨앗 첨가구는 19％ 대치한 구에서는 전 산란기간을 통하여 반 생산 및 능력이 대조구에 비하여 아무 차이가 없었다. 그러나 38％ 대치구에서는 약간의 성성숙 지연이 있었지만 전 산란기간을 통하여 얻어진 시험결과에 의하면 오히려 경제적으로 이익이었다.

• 한국가금학회지
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• 제9권1호
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• pp.35-42
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• 1982

본 연구는 산업계의 산란능력을 개량하는데 있어서 부분검정의 효율성을 구명하기 위하여 White Leghorn 합성종계통 선발 1세대의 478수에서 측정된 산란기록을 분석자료로 이용하였다. 조사된 형질은 초산일령, 40주령까지의 산란수(P) 및 산란율(P'). 41주령에서 64주령까지의 산란수(R) 및 산란율(R'), 그리고 전체산란수(A) 및 산란율(A') 이었으며, 초산일령부터 40주령까지의 단기검정성적을 다시 세분하여 초산일령에서 22주, 24주, ㆍㆍㆍㆍ, 40주까지 2주씩 더해 나간 기간동안의 산란수(E$_{t}$) 및 산란율(E'$_{t}$), 그 반대로 40주령까지의 성적을 최초의 초산일령 19주령 부터, 2주씩 제외시키고 얻은 나머지 기간의 산란수(S$_{t}$) 및 산란율(S'$_{t}$)을 각각 구하여 상대적 효율을 비교하였다.을 비교하였다.

• 한국가축번식학회지
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• 제9권2호
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• pp.124-132
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• 1985

The work was conducted to clarify the development of testes and histological changes of the Seminiferous tubules that is the Surface area, diameter, length of the tubules and the process of Spermatic cells growth in Seminal epithelium in relation to Sexual maturity of the meat-type cockerels. In addition the present experiments were planned to gain some basic data helpful for the study of reproductive physiology in meat-type cockerels and also to compare the histological changes Seminiferous tubules between egg and general purpose type cockerels. 1. The growth pattern of body weight, testes and comb was classified into four phase according to age. Body weight increased up to about 2kg at 2nd stage and to 4.3kg at 4th stage while at 3rd stage the growth rate of body weight was slower. The tests developed slowly until 22 weeks of age with no correlation to the growth of body weight. However, it grew rapidly afterwards, reaching 27.79$\pm$9.26gm and 42.46$\pm$5.33 gm at 24 and 28 weeks of age, respectively. The spermatozoa was seen first at 24 weeks of age. On the other hand, comb grew at similar rate to the testes, weighing on the average 21.78$\pm$6.48gm and 41.42$\pm$1.25gm at 24 and 28 weeks of age, respectively. 2. The areal rate of the Seminiferous tubules to interstitial tissues was 66%:34% at 2 weeks of age and the rate of the former increased in comparison to that of the latter as they grew older, becoming 94%:7% between at 24 weeks of age, when the testes weight increased rapidly too. 3. Diameter of Seminiferous tubules at 2 weeks of age was 42.76$\pm$1.04$\mu$m and then it gradually increased as the testes grew until 22 weeks of age, when it grew rapidly, increasing about 2.9 times of those of 2 weeks and at last increased up to 5 times at 24 weeks. 4. Length of Seminiferous tubules was 4.5cm at 2 weeks and then it was gradually increased. At 22 weeks old the length of tubules was icnreased rapidly being 321 meter and increased more than double, being 658 meter at 24 weeks old. 5. The cells of Seminal epithelium developed poorly and the number of cells were relatively few until 16 weeks old. Afterwards the cells increased rapidly in number and at 18 weeks, the number became twice of those of 16 weeks, reaching 140.43$\pm$43.6. At 24 weeks the cells increased more rapidly, reaching to 10 layers and Spermatozoa were first time seen.

• Asian-Australasian Journal of Animal Sciences
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• 제5권1호
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• pp.165-171
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• 1992

The developmental process of the epididymis was investigated in Meishan boars from 1 to 364 days of age. Epididymal weight increased rapidly between 45 and 150-180 days of age. The diameter and epithelial area of the epididymal ducts greatly increased up to 105-120 days of age. At 1 day of age, the central and distal cauda already had a pseudostratified epithelium surrounded by smooth muscle. At 60-75 days of age, the central and distal caput, corpus, and proximal cauda revealed a well-developed structure of the epithelium. The proximal caput showed a tall, irregular and vacuolar epithelium at 105-120 days of age. PAS-positive contents in the lumen of the caput, corpus and cauda epididymides were first detected at 60-75, 45-60 and 1-30 days of age, respectively. Moreover, in the central and distal caput, PAS-positive granules appeared at 60-75 days of age, and increased until 105-120 days. These results suggest that the epididymis develops completely by approximately 120 days of age, though its weight increases rapidly up to 150-180 days. Thus, it appears that development of the epididymis occurs at an earlier age in Meishan boars than in European and American breeds.

• 한국발생생물학회지:발생과생식
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• 제16권3호
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• pp.205-217
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• 2012

The ovarian cycle, the biological minimum size, and artificial spawning frequency by artificial spawning induction of the female hard clam, Meretrix petechialis, were investigated by histological observations and morphometric data. The ovarian cycle of this species can be classified into five successive stages: early active stage, late active stage, ripe stage, partially spawned stage, and spent/inactive stage. The spawning period was from June to September, and the main spawning occurred between July and August when the seawater temperature exceeds over $20^{\circ}C$. The biological minimum size (shell length at 50% of first sexual maturity) in females were 40.39 mm in shell length (considered to be two years of age), and all clams over 50.1 mm in shell length sexually matured. In this study, the mean number of the spawned eggs by spawning induction increased with the increase of size (shell length) classes. In case of artificial spawning induction for the clams > 40.39 mm, the number of spawned eggs from the clams of a sized class was gradually decreased with the increase of the number of the spawning frequencies (the first, second, and third spawning). In the experiments of artificial spawning induction during the spawning season, the interval of each spawning of this species was estimated to be 15-18 days (approximately 17 days).

• Journal of Preventive Medicine and Public Health
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• 제37권1호
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• pp.72-79
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• 2004

Objectives : This cross-sectional study aimed to quantify the relationship between the bone mineral density at the os calcis and the body mass composition in healthy children. Methods : The areal bone mineral density was measured at the os calcis with peripheral dual energy X-ray absorptiometry. The fat free mass, fat mass and percentage fat mass were measured using bioelectric impedance, in 237 Korean children, aged 9 to 12 years. The sexual maturity was determined by self assessment, using standardized series of the 5 Tanner stage drawings, accompanied by explanatory text. Results : From multiple linear regression models, adjusted for age, sexual maturity and height, the fat free mass was found to be the best predictor of the calcaneal bone mineral density in both sexes. About 15 and 20% variabilities were found in the calcaneal bone mineral densities of the boys and girls, respectively, which can be explained by the fat free mass. After weight adjustment, the percentage fat mass was negatively associated with the calcaneal bone mineral density in both sexes. Conclusions : The findings of this study suggest that the fat free mass, among the body compositions, is the major determinant of bone mineral density at the os calcis in Korean children aged 9 to 12 years. Obesity, defined as the percentage fat mass, is assumed to have a negative effect on the calcaneal bone density in children of the same weight.

• Asian-Australasian Journal of Animal Sciences
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• 제20권11호
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• pp.1684-1688
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• 2007

This study examined the caponization effects on the muscle characteristics (quality and quantity) of caponized male chickens fed before or after sexual maturity. Healthy and uniform Single Comb White Leghorn chickens were caponized at 3-week-old. Feeding was conducted until 16-week-old in trial 1 or from 12-week-old to 26-week-old in trial 2. Ten sham operated male chickens (Sham) were also assigned to each trial as the control group. Chickens used in both trials were housed in individual cages with each chicken representing one replicate. The results showed that early caponization (3-week-old) significantly increased (p<0.05) body weight and pectoral major muscle weight and percentage at 16-week-old compared to the Sham in trial 1. Caponization significantly increased (p<0.05) the protein content of the pectoral major muscle, but decreased (p<0.05) the ash content. Late caponization (12-week-old) significantly decreased (p<0.05) the ash content, myofibrillar ATPase activity and emulsification capacity of the pectoral major muscle in mature capons (26-week-old) compared to the Sham in trial 2. Early caponization (3-week-old) only increased the weight and protein content of the pectoral major muscle with decreased ash content in 16-week-old capons. Late caponization (12-week-old) showed no affects on pectoral major muscle quantity, while it decreased the ATPase activity and enhanced the emulsification capacity in mature (26-week-old) capons. Hence, the muscle quality improvement was shown as capons were fed to sexual maturity.

• Asian-Australasian Journal of Animal Sciences
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• 제25권9호
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• pp.1338-1350
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• 2012

This review focuses on the nutritional effects from birth until age at first calving on growth, mammary developmental changes, and first-lactation milk yield in heifer calves. The advancement in the genetic potential and the nutritional requirements of the animals has hastened the growth rate. Genetic selection for high milk yield has suggested higher growth capacity and hence increasing nutritional inputs are required. Rapid rearing by feeding high energy or high concentrate diets not only reduces the age of sexual maturity but also lowers the time period of attaining the age of first calving. However, high energy diets may cause undesirable fat deposition thereby affecting future milk yield potential. Discrepancies exist whether overfed or overweight heifers at puberty can influence the mammary development and future milk yield potential and performance. The data on post-pubertal nutritional management suggested that body weight at calving and post-pubertal growth rate is important in first lactation milk yield. There is a continuous research need for strategic feeding that accelerates growth of dairy heifers without reduction in subsequent production. Nutritional management from birth, across puberty and during pregnancy is critical for mammary growth and for producing a successful cow. This review will mostly highlight studies carried out on dairy breeds and possible available opportunities to manipulate nutritional status from birth until age at first calving.