EVALUATION OF THE HEALTH-STATUS OF DAIRY HERDS

A survey was conducted in 108 farms from four departments : Loire-Atla ntique, Moselle, Oise and Seine-Maritime. The objective of this study was to study the link between an overall measure of health status and technical-economic indicators. The overall health status was assessed as the arithmetic mean of the scores given to the values observed for each of the 12 variables used to characterise the pathological entity, equal to -1, 0 or 1. The variables having a technical-economic import ance were the difference between the objective and actual level of mil k production (favourable when the value was negative), calf and young bovine mortality from illness (opposed to death at calving, the former was considered as a variable characterising a pathological entity), c ulling due to illness (for animal which if not for the illness would n ot have been culled) and veterinary costs (expressed per cow in the he rd). The analysis of multiple correspondents showed that there were tw o opposite types of farms : 52 farms with a health problem and 23 farm s with a favourable health situation and 33 which were situated in-bet ween. However, the milk cell number variable was independent of the ot her variables characterised by a pathological entity. In addition, it seems to be associated with the culling policy for health reasons, whi ch is itself linked to the size of the herd. The technical-economic in dicators of health status were significantly different according to wh ether they corresponded to a favourable, intermediary or unfavourable overall health status. This finding tends to support the consistency o f the overall health status score.