Reproductive performance of a cow-calf herd following a Neospora caninum-associated abortion epidemic.
This study examines the long-term impact of a Neospora caninum-associated abortion outbreak in a large cow-calf herd in northern Alberta. Blood samples were collected 4 times from all bred females and heifer calves born during the spring before the outbreak: (1) at the time of the outbreak, (2) the following spring, (3) the subsequent fall, and, finally, (4) the second spring after the outbreak. The samples were analyzed using a commercially available enzyme-linked immunosorbent assay for N. caninum. Calves born immediately following the outbreak were also monitored. Individual calving or abortion records were available from all cows for 2 calving seasons. All cows and heifers were pregnancy tested after the 2 subsequent breeding seasons. At the time of the abortion outbreak in 1997, 81% of all bred females and 87% of the heifer calves were serologically positive. In spring 1998, 49% of the cows and 47% of the heifer calves remained positive. In fall 1998, 48% of the remaining cows and heifers were serologically positive. After the first breeding season following the outbreak (1998), 13.5% of the heifers and 22.2% of the cows were open (not pregnant). Animals that were serologically positive in the spring were more likely to be open in the fall (odds ratio, 2.0; 95% confidence interval, 1.1 to 3.7). No subsequent associations with increased risk of abortion, stillbirth, or nonpregnancy were identified.
Waldner
C L
CL
Department of Large Animal Clinical Sciences, Western College of Veterinary Medicine, 52 Campus Drive, University of Saskatchewan, Saskatoon, Saskatchewan S7N 0W0.
Henderson
J
J
Wu
J T
JT
Breker
K
K
Chow
E Y
EY
D000034:Abortion, Veterinary / Q000453:epidemiology* / Q000469:parasitology; D000416:Alberta / Q000453:epidemiology; D000818:Animals; D000913:Antibodies, Protozoan / Q000097:blood; D002417:Cattle; D002418:Cattle Diseases / Q000453:epidemiology / Q000469:parasitology / Q000503:physiopathology*; D003048:Coccidiosis / Q000453:epidemiology / Q000503:physiopathology / Q000662:veterinary*; D004196:Disease Outbreaks / Q000662:veterinary*; D004797:Enzyme-Linked Immunosorbent Assay; D005260:Female; D008137:Longitudinal Studies; D008297:Male; D018688:Neospora / Q000276:immunology / Q000472:pathogenicity; D016017:Odds Ratio; D011247:Pregnancy; D015597:Pregnancy Complications, Parasitic / Q000453:epidemiology / Q000503:physiopathology / Q000662:veterinary*; D012098:Reproduction; D016036:Seroepidemiologic Studies; D013997:Time Factors
D000913:Antibodies, Protozoan