NR AUMO
AU Ovelhey,A.
TI Epidemiologische Untersuchung zum Bestandsmanagement in Rinder haltenden Betrieben in Niedersachsen unter besonderer Berücksichtigung von Risikofaktoren für das Auftreten von BSE und Paratuberkulose
QU Inaugural-Dissertation zur Erlangung des Grades einer Doktorin der Veterinärmedizin (Dr. med. vet.) durch die Tierärztliche Hochschule Hannover, vorgelegt von Amely Ovelhey aus Hannover, 2.6.2005
QU Vet. med. Dissertation Tierärztliche Hochschule Hannover, 2005
PT Dissertation
AB Parameters of farm structure and management can be considered as important for the development of diseases in livestock production. Often the same management parameters are of interest and these may not be affected by the type of infection or disease. Therefore, it is the aim of this study to survey information about parameters of farm management on cattle farms. A representative study population was to be generated in order to draw conclusions on the whole cattle population in Lower Saxony. The results were to be compared with information about affected populations to make a statement about the risk factors of BSE and Johne's disease in cattle farms in Lower Saxony. Hence a cross-sectional study was conducted. The double-phase study design was twice integrated. Data was surveyed by a postal questionnaire and personal interviews on farms. By following up the nonresponders it was possible to generate a representative study population. Although the postal questionnaire was long, a response rate of 40 % was achieved due to the layout, the concept, the letter of information and the follow up letter, which was sent to nonresponders after a certain time. This made a precise enough statement possible. The results of the study corresponded with official statistics regarding the number of cattle or cows and the distribution among the counties. As there were no discrepancies between the two phases of survey, the results can be regarded as representative for the whole cattle population in Lower Saxony. Data supplied by 731 farmers was incorporated in the analysis. In 2003 the average sized farm had a cattle population of 88 animals. Between 1994 and 2003 the proportion of dairy cattle holding farms decreased from 69 % to 55 %. It was determined from the information about feeding calves and young cattle, that the use of milk replacer decreased in the years 1994 to 2003 from 45 % to 39 %. The use of milk replacer in total was lower than assumed. Comparison with the BSE population in Lower Saxony showed that BSE was found predominantly in big herds with dairy cattle during the study period. Red Holstein cattle were most at risk of a BSE infection. Furthermore, milk production was reduced in BSE-infected cattle compared to the study population. Therefore, other parameters, which were not investigated in this study, could have an influence on the risk of a BSE infection. There was no reference to an increased risk through cross-contamination, the use of milk replacer or concentrated food for calves or the purchase of cattle. The size of farms was included in the analysis of these parameters although a relevant influence of this parameter on other parameters in dairy holding cattle farms was not observed. Conclusions on risk factors for Johne's disease were difficult due to a small number of positive samples in bulk milk. Leaving the calf with the mother postpartum seemed to have a protective effect on infection. It seemed to be likely, that the risk of MAP transmission was higher if equipment was used for both young and adult cattle and if changes of staff, responsible for feeding calves, were frequent. For more detailed conclusion further research should be made on BSE by a casecontrol study and on Johne's disease concerning distribution and risk factors in Lower Saxony. A representative collective was generated in this study. It can be used in future research on several diseases for a comparison with a healthy population.
SP deutsch
PO Deutschland