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The methodology of Event History analysis and its application in the quality control of raw milk
74-79Views:101Event-history analysis is among the most frequently adopted mathematical methods, mainly due to the numerous types of models, available in the analysis. This method is also appropriate for analysing risk. Specifically, it has been employed in medical and animal-breeding science to manage risks. In this article, I give a presentation of the basic concepts, the basic types of models and their theoretical basis. I deal with the nonparametric Kaplan Meier and the parametric Cox proportional hazard model. The case study is also analysed with these methods. The results shows, that the 16-stall caroussel is the most effective facility from the viewpoint of quality. Milking into assay crucible (sample- cup) is more effective than to the floor after 16 decades.
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Effect of floor type and bedding system on sows lifespan
155-160Views:126The paper studies two nucleus pig farms in the Great Plain region of Hungary which have same management, same feeding system but different breeding technology (Farm A had solid floor with straw and Farm B had slatted floor without straw). The genetics of sows were crossbred Dutch Large White and Dutch Landrace. The comparative examination was based on the causes of culling according to the different floor type. To the analysis of culling reasons was applied the methods of survival analysis.
In the analysis there were used the Kaplan-Meier method and the Cox Proportional Hazard model to the estimate the difference between the farms. The results of survival analysis showed significant difference (p<0.05) between the lifespan of sows that caused the difference between the survival probabilities of sows culled due to lameness. Furthermore there was showed that the sows kept on solid floor with straw have stayed in production longer than on slatted floor without straw. The hazard ratio was 1.434 that means that the culling due to lameness is 1.434 times higher by the slatted floor without straw facing by solid floor with straw.
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Assessment of Environmental Susceptibility/Vulnerability of Soils
62-74Views:102Soils represent a considerable part of the natural resources of Hungary. Consequently, rational land use and proper soil management – to guarantee normal soil functions – are important elements of sustainable (agricultural) development, having special importance both in the national economy and in environment protection.
The main soil functions in the biosphere are as follows: conditionally renewable natural resource; reactor, transformer and integrator of the combined influences of other natural resources (solar radiation, atmosphere, surface and subsurface waters, biological resources), place of „sphere-interactions”; medium for biomass production, primary food-source of the biosphere; storage of heat, water and plant nutrients; natural filter and detoxication system, which may prevent the deeper geological formations and the subsurface waters from various pollutants; high capacity buffer medium, which may prevent or moderate the unfavourable consequences of various environmental stresses; significant gene-reservoir, an important element of biodiversity.
Society utilizes these functions in different ways (rate, method, efficiency) throughout history, depending on the given natural conditions and socio-economic circumstances. In many cases the character of the particular functions was not properly taken into consideration during the utilization of soil resources, and the misguided management resulted in their over-exploitation, decreasing efficiency of one or more soil functions, and – over a certain limit – serious environmental deterioration.
Soil resources are threatened by the following environmental stresses:
– soil degradation processes;
– extreme moisture regime;
– nutrient stresses (deficiency or toxicity);
– environmental pollution.
Environmental stresses caused by natural factors or human activities represent an increasing ecological threat to the biosphere, as well as a socio-economic risk for sustainable development, including rational land use and soil management.
The stresses are caused by the integrated impacts of various soil properties, which are the results of soil processes (mass and energy regimes, abiotic and biotic transport and transformation and their interactions) under the combined influences of soil forming factors. Consequently, the control of soil processes is a great challenge and the main task of soil science and soil management in sustainable development.
The efficient control of these processes necessitates the following consecutive steps:
• registration of facts and consequences (information on land and soil characteristics, land use, cropping pattern, applied agrotechnics, yields, with their spatial and temporal variability);
• evaluation of potential reasons (definition and quantification of soil processes, analysis of influencing factors and their mechanisms);
• assessment of the theoretical, real, rational and economic possibilities for the control of soil processes (including their risk-assessment and impact analysis);
• elaboration of efficient technologies for the „best” control alternatives (best management practice).
Scientifically based planning and implementation of sustainable land use and rational soil management to ensure desirable soil functions, without any undesirable environmental side-effects, require adequate soil information. In the last years such data were organized into a computer-based GIS soil database in Hungary, giving opportunities for the quantification, analysis, modelling and forecasting of the studied environmental stresses and for the efficient and scientifically based prevention, elimination or reduction of environmental stresses and their unfavourable ecological and economical consequences.
Special attention was paid to the assessment of various soil degradation processes, as: (1) soil erosion by water or wind; (2) soil acidification; (3) salinization and/or alkalization; (4) physical degradation (structure destruction, compaction); (5) extreme moisture regime: drought sensitivity and waterlogging hazard; (6) biological degradation; (7) unfavourable changes in the plant nutrient regime; (8) decrease of natural buffering capacity, (9) soil (and water) pollution.
The actions against undesirable environmental stresses and their unfavourable consequences are important elements of sustainable, efficient, economically viable, socially acceptable and environmentally sound crop production and agricultural development. These are joint tasks of the state, decision makers on various levels, the land owners, the land users and – to a certain extent – of each member of the society. -
Analysis of the Station Test Results of the Hungarian Large White and Hungarian Landrace Populations Applying Survival Analysis
37-40Views:91Authors analysed the days of fattening in relation to the station test for Hungarian Large White and Hungarian Landrace pig populations using, survival analysis. Survival and hazard functions were calculated in both groups separately for castrates and females. The log-rank test was applied to determine the significance of the differences across the groups. Authors established that within the breeds the functions of the castrates and females were significantly different, namely the castrates reached final weight sooner or, in cases where final weight was not reached by a certain period, castrates reached this weight during the next time unit with a higher probability than the females.
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Survival analysis of sow longevity and lifetime reproductive performance – Review
75-80Views:331Sow longevity plays an important role in economically efficient piglet production. Improving sow longevity results increase in the productivity and profitability of a sow herd. Longevity is a complex trait with many factors that can contribute to a sow having a long and productive life. Not only the sow’s genetics, but also nutrition, environment and the management policies are important. In addition, the removal of non-productive sows along with the introduction of replacement gilts is an essential part of maintaining herd productivity at a constantly high level. The objective of this paper was to summarize the current knowledge about the sow longevity and lifetime performance values, as well as, discusses the survival analysis methods for sow longevity traits. This method can estimate the hazard rate indicating proportional risk of sows being culled at any given time, in addition, it is able to investigate the effects of different factors on longevity. Identifying factors that influence the longevity could assist many commercial pig producers in becoming more efficient.
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Application of the decision tree, as the weak point of the HACCP system development
63-70Views:120In this article we have compared the „decision tree” method –suitable for the CCP determination during the HACCP systemintroduction – with the objective measurement method. We have found out, that the CCP-s from the two method differ from each other. So, the empirical „decision tree” method is suitable for determination of CCP-s only limited, while the measurementbased method determines the CCP-s objectively. Only the right
CCP-determination can guarantee safe food.