• Journal of Environmental Science International
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• v.30 no.3
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• pp.289-293
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• 2021

This study was conducted to investigate the distribution of duck production in duck housing as a function of the breeding period. The items in duck production distribution included body weight, feed intake, feed conversion ratio, and average duck production. All data were based on eight cycles (June and December, 2017; February, June, August, September, and November, 2018; February, 2019) at Farm Site 1 through 7. The most optimal results in the duck production distribution were observed at Site 1 for weight gain, feed intake, and feed efficiency. This could be explained by the fact that Site 1 was well managed in environmental improvement and sustainability. Based on these data, selective alternatives to improve duck production in duck farms are recommended as follows: first, proper management and recording of litter used as a flooring material are required, and second, continuous management such as temperature, relative humidity and ventilation is needed. Lastly, it is necessary to change duck facilities by introducing environmental management techniques. Furthermore, efforts to improve the overall facilities and management of duck breeding farms through additional field studies are needed in the future.

• The Korean Journal of Ecology
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• v.14 no.2
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• pp.171-179
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• 1991

In this study, the balnce of the litter production and decompsition on the forest floors in the green belt nearby seoul, which had been established in 1972, and turnover cycles of minerral nutrients were inverstigated. litter production and decomposition in the forests of quercus accutissima, q, serrata, q. mongolica, salix koreensis and alnus hirsuta were reached at the equilibium stated from 1972 to 1988 but this balance in the pine forest of pinus densiflore and p. rigida was not. Under the forests in the blance of the litter production and decomposition, the maximum amounts of n, p, k, ca and na retured to soil annually were 4.9g/㎡ in the alnus hirsuta forest, 0.35g/㎡ in the salix koreensis forest, 2.70g/㎡ in the quercus accutissima forest, 8.85g/㎡ in the s. koreensis forest and 3.93g/㎡ in the s. koreensis forest, respectively, and the minimum were 2.8g/㎡ in the s. koreensis forest, 0.108g/㎡ in the q. mongolica forest, 0.06g/㎡ in the s. koreensis forest, 2.12g/㎡ q. mongolica forest and 0.15g/㎡ in the q.accutissima forest.

• The Korean Journal of Ecology
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• v.13 no.1
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• pp.51-58
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• 1990

The rates of litter production and decomposition of litters from grasslands and forests in Mt. Guryong were studied. The annual litter production of Glycine soja showed the highest value 1950.88 g/$m^2$/yr in the grasslands and that in Quercus acutissima, as 2202.38 g/$m^2$/yr in the forests. The highest decay rate of the grasslands was found in G. soja as k=0.713 and that of the forests was in Salix koreensis as k=0.319. The Z values of k in the grasslands was higher than that in the forests. The shortest half-time of the litter decay in the grasslands was 0.9 years in G. soja and the longest one of the forests was S. koreensis as 2.1 years and the longest of all was Q. mongolica as 5.2 years. In the amount of total nitrogen of litters, G. soja was the highest of the grasslands and S. koreensis was the highest of the forest. The content of the total nitrogen in litters was directly propotional to the decay rates.

• Animal Bioscience
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• v.37 no.4
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• pp.678-688
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• 2024

Objective: Reduced crude protein (CP) diets offer potential benefits such as optimized feed efficiency, reduced expenses, and lower environmental impact. The objective of this study was to evaluate black soldier fly larvae (BSFL) meal on a low-protein diet for duck performance, blood biochemical, intestinal morphology, gastrointestinal development, and litter. Methods: The experiment was conducted for 42 days. A total of 210-day-old male hybrid ducklings (5 replicate pens, 7 ducks per pen) were randomly assigned to 6 dietary treatments (3×2 factorial arrangements) in randomized design. The factors were CP level (18%, 16%, 14%) and protein source feed soybean meals (SBM), black soldier fly larvae meals (BSFLM). Results: Reduced dietary CP levels significantly decreased growth performance, feed intake, the percentage of nitrogen, pH (p<0.05), and tended to suppress ammonia in litter (p = 0.088); increased lipid concentration; and enhanced relative weight of gastrointestinal tracts (p<0.05). In addition, dietary BSFL as a source of protein feed significantly increased lipid concentration and impacted lowering villus height and crypt depth on jejunum (p<0.05). Conclusion: In conclusion, the use of BSFLM in a low-protein diet was found to have a detrimental effect on growth performance. However, the reduction of 2% CP levels in SBM did not have a significant impact on growth performance but decreased nitrogen and ammonia concentrations.

• Korean Journal of Poultry Science
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• v.40 no.3
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• pp.253-262
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• 2013

This experiment was conducted to investigate the effects of floor type and heating system on performance, housing environment and health status of ducks reared in three types of duck house (OD : Open floor house-Direct heating system, OF : Open floor house-Floor heating system and LD : Loft type house-Direct heating system). In OF treatment, PVC pipes were installed for heating under concrete floor and covered with litter. In LD treatment, plastic mesh was installed 50 cm above the floor so that duck's droppings can pass through it. Each treatment had four replicates of 25 birds (Cherry Valley duck breed) per pen. There were no significant differences in weight gain and feed intake of ducks for 6 weeks among all treatments. However, feed conversion ratio in LD was significantly higher (p<0.05) than that in OF. No differences were found in carcass charac- teristics, with the exception of abdominal fat weight where OF were higher than the others. Concentrations of $CO_2$ and $NH_3$ gas in OD were higher than those of OF and LD at 3, 4 and 5 weeks. Moisture content in litter of OF was lower than that of OD. In contrast, the amount of dust in the air was higher in OF than in OD. The amount of fuel used for 6 weeks in LD was lower about 21% than that in OD. Some of unusual symptoms were observed in open floor house and loft type house, such as lying, spraddle legged, twisted ankle and legs, wounded sole, or etc. No components of leukocyte and erythrocyte of blood were significantly different among all treatments. The results of this experiment showed that OF and LD systems had no positive effects on performance of meat type commercial duck. However, there were some positive effects of certain house type for the improvement of environmental condition in duck house for hygienic production. In the future, more research on the effect of various facilities and systems for duck house is needed.

• Journal of Animal Science and Technology
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• v.53 no.4
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• pp.333-339
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• 2011

The present study was performed to investigate the effects of pre- and post-weaning feeding programs on growth of pigs. A total of 24 litters (avg. 10.6 piglets/litter) born from multiparous (Yorkshire ${\times}$ Landrace) dams ${\times}$ Duroc sires were provided with neither creep feed (CF) nor milk replacer ("CON"), 200 gm CF/litter/d from the 15th day of lactation ("MIN"), or CF and milk replacer ad libitum for 7 h during the daytime from the 7th day ("MAX") through weaning at d 21 of age. Sixty-eight weanling pigs selected randomly from each of CON and MIN were provided with phases 1, 2 and 3 nursery diets for 7, 14, and 13 days, respectively, in two pens; an equal number of piglets from MAX received the same diets for 6, 10, and 18 days, respectively. Subsequently, all pigs were fed grower 1 and 2 diets sequentially up to d 95 and 135, respectively. The entire pre- and post-weaning feeding trial was repeated three times under a split-plot design of experiment. Initial and final weights and ADG of the suckling pigs did not differ between MAX/MIN and CON. However, final wt of MAX adjusted for initial wt, which was 0.17-kg less in MAX than in CON, was greater than that of CON by 0.31kg, whereas the difference between MIN and CON in final wt barely changed after the adjustment. Growth of the animals during the nursery and growing phases was not affected by the feeding program, whereas d 55 and 135 BW, as well as d 6 BW, were highly correlated with weaning weight (r=0.81, 0.57, and 0.76; P<0.001, <0.05, and <0.001, respectively). In conclusion, results suggest that provision of creep feed and milk replacer from early lactation may be effective for increasing weight gain of light piglets, but that limited provision of creep feed during late lactation or extension of the duration of phases 1 and 2 vs. 3 nursery diets for several days is unlikely to influence the growth of pigs during the corresponding and subsequent periods.