Beta 1

Title Climate and Campylobacter in broilers
Author Iskandar, Amne
Johansen, Tine
Supervisor Christiansen, Lasse Engbo (Mathematical Statistics, Department of Informatics and Mathematical Modeling, Technical University of Denmark, DTU, DK-2800 Kgs. Lyngby, Denmark)
Institution Technical University of Denmark, DTU, DK-2800 Kgs. Lyngby, Denmark
Thesis level Bachelor thesis
Year 2008
Abstract This report consists of three parts. Each part is a case study of the correlation between variables. All cases are based on the statistical method local linear regression and the cross validation error was used to select the most optimal model and to avoid over fitting. In the first part an analysis was set up to study the relationship between the average number of flies and different climate factors. It was found that the temperature has a great impact on the number of flies and the best fitted model included average and maximum temperature together with relative humidity measured three weeks before the registered number of flies. The degree of explanation for this model was calculated to 50.12%. In the second and third part a relation between the share of campylobacter positive broiler flocks at slaughter and the same climatic variables was sought, but the third part differs by the fact that the average number of flies has been added as explanatory variable. In both cases the temperature has a great influence. The best estimated model in the second case include average and maximum temperature, hours with sunshine and precipitation measured four weeks prior to the registration of infected broiler flocks and it explains 64.66% of the variation. In the third case the best model include average and maximum temperature and hours with sunshine three weeks prior to the registration. This model explains 66.62% of the variation. In all three cases the largest increase for the response variable is observed at average temperatures above around 8±C and at maximum temperatures above around 13±C.
Series IMM-B.Sc.-2008-27
Original PDF bac08_27_ny_net.pdf (1.53 MB)
Admin Creation date: 2008-08-26    Update date: 2008-08-27    Source: dtu    ID: 222628    Original MXD