title: An epidemiologic study of late-term abortions in dairy cattle in Denmark, July 2000-August 2003.
abstract: Abortion in dairy cows in well-managed dairies is not common but differences have been reported probably due to variation in animal health, nutrition and management, as well as difficulties in observing the aborted material. A 38-month study of 507 large Danish dairy herds revealed 3354 late-term abortions and 224,419 calvings were recorded. During the study period, a total of 3717 submissions were made to the Danish Institute for Food and Veterinary Research (DFVF). A broad spectrum of abortive agents was isolated but none were found to be statistically associated with abortions. The number of abortions in a month on a dairy was significantly (P<0.001) associated with the number of cows in the third trimester but explained only 11% (R(adj)(2)=0.114) of the variability of the reported abortions. A total of 23 herds (4.5%) reported 531 abortions (15.8%). Although a marginally significant (P=0.11) risk of increased abortions was found to exist in bovine viral diarrhea virus- (BVDV) infected herds, it could be at least partially explained by additional calvings in those herds. Temporal correlation between inseminations and abortions was statistically significant (P<0.001) with the highest correlation (r=0.47-0.51) after lagging abortions on insemination by 6-8 months. No indication of spatial clustering was detected for either specific-abortogenic pathogens or high aborting dairies using either Cuzick-Edwards' (P>0.17) or spatial scan tests (P>0.23). Ederer-Myers-Mantel test was applied to 3 years of data on the highest aborting dairies and showed that July had nearly double the expected number of maximum monthly abortions (P<0.001). These findings provide further insight into the reported abortion pattern in Danish dairies and may facilitate planning future control programs.
authors.affiliation: Center for Animal Disease Modeling and Surveillance, School of Veterinary Medicine, University of California, Davis, CA, USA. tecarpenter@ucdavis.edu
authors.forename: Tim E
authors.initials: TE
authors.lastname: Carpenter
authors.forename: Mariann
authors.initials: M
authors.lastname: Chrièl
authors.forename: Mette M
authors.initials: MM
authors.lastname: Andersen
authors.forename: Liana
authors.initials: L
authors.lastname: Wulfson
authors.forename: Astrid M
authors.initials: AM
authors.lastname: Jensen
authors.forename: Hans
authors.initials: H
authors.lastname: Houe
authors.forename: Matthias
authors.initials: M
authors.lastname: Greiner
mesh_terms: D000034:Abortion, Veterinary / Q000453:epidemiology* / Q000209:etiology*; D000818:Animals; D001424:Bacterial Infections / Q000150:complications / Q000662:veterinary; D001912:Bovine Virus Diarrhea-Mucosal Disease / Q000150:complications*; D002417:Cattle; D002418:Cattle Diseases / Q000175:diagnosis*; D003048:Coccidiosis / Q000150:complications / Q000662:veterinary; D003612:Dairying / Q000379:methods; D003718:Denmark; D005260:Female; D015994:Incidence; D011247:Pregnancy; D012307:Risk Factors; D012621:Seasons; D013029:Space-Time Clustering