Management and herd performance of dairy herds with and without 'chronic wasting' cows

'Chronic wasting' in cattle acquired a special meaning in the Netherlands i n 1999. It was used to define animal health problems that were thought to b e associated with the use of bovine herpesvirus 1 marker vaccine. Criteria have not been set by which an objectively independent inventory of the prob lems could be made. The objective of this study was to determine management factors associated with the problem of 'chronic wasting' prior to the use of the BHV1 marker vaccine. Knowledge about these factors could be helpful for generating additional hypotheses about the aetiology of chronic wasting in cattle. A total of 188 farms participated in the study, of which 94 had severe prob lems with chronic wasting. The other half consisted of control farms matche d with the case farms that did not report problems after the use of the BHV 1 marker vaccine. Data analyses were performed over the period before (and not at the time of) 'chronic wasting' problems. Data were collected from va rious sources. A questionnaire was used to collect information on farm mana gement practice. In addition, information on laboratory submissions for 199 6 to 1998, animal movements in 1998, roughage analyses of 1997 and 1998, ex penses for animal health in 1998, and herd performance in 1995 to 1999 was collected. In the analyses, a distinction was made between information obta ined objectively and subjectively. Herds with problems of 'chronic wasting' were larger than herds without wasting problems (animals, surface) but not more intensively managed. 'Wasting' herds had a lower performance in terms of fertility and udder health. In addition, these herds had more contact w ith other herds through the purchase of animals. There were no differences in farm management practices related to disease control and prevention. Add itional studies are required with regard to the patho-physiology of chronic wasting cows. The role of herd size needs more study.