Neospora caninum is an obligate intracellular protozoon
first isolated in Norwegian dogs [1]. Neosporosis has
emerged as a serious disease causing abortions and
neonatal mortality in cattle [2]. The dog was identified as
the definitive host of N caninum when shown to be able toeliminate oocysts after experimental inoculation [3].
Infected cows demonstrate prominent transplacental
transmission (w95%), and most calves born from infected
mothers are clinically normal but are infected for life [2].
Serologic examination is an efficient diagnostic tool [4].
Cows infected with N caninum showgreater likelihood of
pregnancy loss than uninfected ones [5–8]. The gestational
age of aborted Neospora-infected fetuses has been reported
mostly from the fifth to seventh month of pregnancy [9].
Most studies evaluated the impact of N caninum infection in
herds with high incidence of abortion, and generally,
without a systematic control against other potential infectious
agents causing abortion. The potential impact of
N caninum infection on pregnancy after parturition or
abortion in grazing dairy cows is not fully recognized.
The aim of this study was to evaluate the relationship
between antibody titers against N caninum before pregnancy
in grazing dairy cows from herds with a systematic
control of other infectious diseases, such as brucellosis,
infectious bovine rhinotracheitis (IBR), bovine viral diarrhea
(BVD), and leptospirosis. Cows were monitored from
conception, throughout gestation, until the subsequent
pregnancy or culling after parturition or abortion. The
impact of spontaneous N caninum infection and its prevalence
on postpartum alterations (i.e., retained placenta,
metritis, and mastitis) and subsequent reproductive performance
was analyzed.