Using artificial insemination data to identify the impact of an abortive disease in dairy cattle herds

Abstract

This article is aimed at discussing the feasibility and advantages of using artificial insemination data, through a new indicator of mid-term abortions, the mid-term abortion incidence rate, in order to identify the impact of an abortive event retrospectively or prospectively. Two studies are used to illustrate the purpose, based on the analysis of mid-term abortion incidence rate to estimate the impact of the Bluetongue serotype 8 (BT8) epizootic that emerged in France in 2006 and then spread across the country in 2007 and 2008. The first study was a retrospective analysis of the temporal variations of the mid-term abortion incidence rate in each French department enabled to identify a posteriorithe impact of BT8 on abortion occurrence. The second study was based on a weekly analysis of the temporal variations of the mid-term abortion incidence rate, and showed that the impact of BT8 would have been identified 12 weeks after the occurrence of the disease in 50% of thedepartments. These results suggest that there is a need to study the feasibility to implement an integrated surveillance of bovine abortions, based on the mandatory notification of bovine abortions (i.e. the current surveillance system with some improvements) and a syndromic surveillance system (that should be implemented at a lower level than the department, to improve timeliness).