• Journal of agriculture & life science
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• v.44 no.5
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• pp.55-64
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• 2010

This study was conducted to estimate genetic parameters for reproductive traits using multivariate animal models in Yorkshire breed. For the study, 4,989 records for litter traits collected between the year 2001 and 2005 from Yorkshire pigs in K GGP were used. The effects of environmental factors such as farrowing year, parity, weaning to estrus interval (WEI), and suckling period were statistically significant (p<0.05), but farrowing season was not significant, for reproductive traits. The estimates genetic correlations and phenotypic correlations in total number of born and number of suckling, was shown to highly correlated. The genetic correlations were higher than phenotypic correlation. The estimates of heritabilities for reproductive traits, considering permanent environment effects (PE) were much lower than those obtained when permanent environment effects were not considered (NPE) in the model. The estimates of heritabilities were 0.240 and 0.076 for total number of born and 0.187 and 0.096 for number of suckling in NPE, and PE, respectively. These results itivcate that PE should be considered in the statistical mode to estimate more acco ate breeding values.

• Journal of Animal Science and Technology
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• v.52 no.1
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• pp.71-76
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• 2010

The aim of this study was to examine the effect of HACCP system implementation on the budget for medicine use, antibiotic utilization, and productivity of swine farms in Korea. Data were collected form thirty swine farms before and after implementation of HACCP system. Parturition rate, total number of piglets, number of initial weaning piglets, number of weaning piglets, survival rate of piglets after weaning, date of weaning piglets, piglet per sow per year, and market piglet per sow per year tended to be higher after HACCP system implementation. In contrast, price for medicine used per month, number of antibiotic used, the farm number of feeds containing antibiotics in each, growing stages added at the feed company, and the farm number of feeds containing antibiotics in each growing stages added at the swine farm were lower after HACCP system implementation. Due to increase in the feed cost recently, production cost for shipment in HACCP system implemented swine farms had increased in this study. In conclusion, our results indicated that the implementation of HACCP system might be effective in reducing medical expenses and improving the productivity.

• Korean journal of applied entomology
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• v.60 no.2
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• pp.215-220
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• 2021

To establish the systematic biological control system for various insect pests in strawberry under plastic houses, we were investigated the biological traits of lesser strawberry aphid, Chaetosiphon minus (Forbes), as a target pest. The lesser strawberry aphid is adapted to low temperatures while examining the availability of and selecting useful natural enemies. The development, survivorship and reproduction of lesser strawberry aphid were evaluated at four constant temperatures (10, 15, 20, and 25℃). The developmental periods of the nymphal stages ranged from 41.7 d at 10℃ to 9.8 d at 25℃. The developmental threshold temperature and degree day of nymphal stages are 5.5℃ and 185 DD. The reproduction rate (R₀) was higher at 20℃ (30.16) than at 25℃ (22.38). The 50 % survival rate and maximum longevity of adult females were 31 d and 59 d at 20℃, and 25 d and 36 d at 25℃, respectively. The average progeny per female was 35 at 20℃, and 26 at 25℃. We confirmed that compared to other strawberry aphids under plastic houses, the lesser strawberry aphid is more adapted to lower temperatures. It is, therefore, necessary to commercialize natural enemies such as syrphid flies with high activity at low temperatures.

• Journal of agriculture & life science
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• v.50 no.5
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• pp.183-188
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• 2016

This experiment was conducted to investigate the effects of artificial insemination(AI) frequency on reproductive performance of sows. A total of 48 F1 sows(Yorkshire×Landrace) were allocated to 1 of 4 treatments using completely randomized design(CRD). Four experimental treatments were AI frequency from one to four times(AI1, AI2, AI3, AI4) respectively. Estrus detection was done at approximately 09:00 and 21:00 daily by applying back pressure to females with the presence of a mature boar and the weaning to estrus interval(WEI) of all sows were 5~6 day. Sows detected in estrus were mated at 12 hour after and mating interval was 12 hour by treatments. This experiment demonstrated that the lowest farrowing rate was observed AI3 treatment. Frequency of AI did not influence on reproductive performance when WEI was 5-6 day. No significant differences were observed on litter size, born alive and litter birth weight. Consequently, decreased AI frequency did not have any detrimental effect on reproductive performance when estrus detection was adequate. Decreased AI frequency could reduce cost of production of pigs when sows showed normal reproductive performance.

• Korean journal of applied entomology
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• v.55 no.2
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• pp.119-128
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• 2016

This study was conducted to develop temperature-driven models for a population model of turnip aphid, Lipaphis erysimi: nymphal development rate models and apterious adult's oviposition (larviparous) model. Nymphal development and the longevity and fecundity of adults were examined on cabbage at six constant temperatures (10, 15, 20, 25, 30, $35{\pm}1^{\circ}C$, 16L:8D). L. erysimi nymphs did not survive at $10^{\circ}C$. Development time of nymphs increased with increasing temperature up to $30^{\circ}C$ and thereafter slightly decreased, ranging from 18.5 d at $15^{\circ}C$ to 5.9 d at $30^{\circ}C$. The lower threshold temperature and thermal constant were estimated as $7.9^{\circ}C$ and 126.3 degree days, respectively. The nonlinear model of Lactin 2 fitted well for the relationship between the development rate and temperature of small (1+2 instar), large (3+4 instar) and total nymph (all instars). The Weibull function provided a good fit for the distribution of development times of each stage. Temperature affected the longevity and fecundity of L. erysimi. Adult longevity decreased as the temperature increased and ranged from 24.4 d at $20^{\circ}C$ to 16.4 d at $30.0^{\circ}C$ with abnormal longevity 18.2 d at $15^{\circ}C$, which was used to estimate adult aging rate model for the calculation of adult physiological age. L. erysimi showed a maximum fecundity of 91.6 eggs per female at $20^{\circ}C$. In this study, we provided three temperature-dependent components for an oviposition model of L. erysimi: total fecundity, age-specific cumulative oviposition rate, and age-specific survival rate.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.20 no.4
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• pp.428-434
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• 2019

Many countries have interested animal welfare. Similarly, domestic people have concern for the welfare from companion animals to livestock. Environmental enrichments (EE) are tool to enforce the welfare, however, research with sows is limited. Therefore, this study was investigate to effects of environmental enrichments on performance and behavior properties of gestating sows. A total of 30 pregnant sows (Landrace) were assigned into three treatments that control, T1 (plastic device) and T2 (Rice straw). Period of trial was from Mar. 03. 18. to Mary 19. 18. The EE were allotted to center of experimental pen ($11.6{\times}6.0m$). Body weight (BW), backfat thickness (BF) and cortisol were identified at experimental initial or end date. Behavior was recorded during 24 hours on days 91 of gestation, and then analyzed the patterns. BF was reduced (15.73 vs. 16.56 mm; p>0.05) in T1 than control, but Ending BW, total litter size and alive piglets did not differ. Born dead piglets showed lower tendency (1.00 and 0.63 vs. 1.50 heads; p>0.05) in T1 and T2 than control. Similarly, the enrichments declined farrowing mortality (C, 8.68%; T1, 6.86%; T2, 3.40%; p>0.05). Cortisol was not differed among treatments. In the behavior characteristics, eating showed lower (1.81 vs. 9.68 and 6.99%; p<0.05) in T2 than control and T1. Furthermore, playing or digging were only observed (0.33 and 2.10%; p<0.05) in T1 and T2, respectively, whereas rubbing (0.91%, p<0.05) only showed in the control. These results suggest that the provision of EE would be not negatively affected the performance of the gestating sows and could be led to improvement of the livestock welfare.

• Journal of Korean Society of Forest Science
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• v.65 no.1
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• pp.92-95
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• 1984

The status of the forest owners and the ownership arrangement has been surveyed in the joint ownership forest of the total 250.59 ha, 17 plots including plot No. 2, in Cha-ri, Duseo-myeon, Ulju-gun, Kyongnam. It has been surveyed that the total number of the practical owners relevant to the ownership is 133 persons. However, the number of the owners is recorded as 55 person in the official documents and there has been a big difference between the number of the practical owners and that of the practical owners and that of the owners in the official documents. As 79 forestowners, 59% of the total forestowners, can not be certainly guaranteed in the execution of their legal rights to the ownership, it could be one of the factors which will hinder the promotion of the investment willingness to forest works. In order to go through with the formality of the ownership registration correspond to reality, some necessary works such as the boundary survey should be followed. Therefore it is required that any governmental or public organizations should take part in technical and financial aids to solve these matters.