AUTHOR=Lagomarsino Horacio , Scioli Agustín , Rodríguez Alejandro , Armendano Joaquín , Fiorani Franco , Bence Ángel , García Joaquín , Hecker Yanina , Gual Ignacio , Cantón Germán , Odeón Anselmo , Campero Carlos , Moore Dadín 

TITLE=Controlling Endemic Neospora caninum-Related Abortions in a Dairy Herd From Argentina

JOURNAL=Frontiers in Veterinary Science

VOLUME=Volume 6 - 2019

YEAR=2019

URL=https://www.frontiersin.org/journals/veterinary-science/articles/10.3389/fvets.2019.00446

DOI=10.3389/fvets.2019.00446

ISSN=2297-1769

ABSTRACT=After diagnosis of endemic abortions due to neosporosis in a commercial dairy farm, routes of Neospora caninum-transmission were evaluated in order to determine the best strategy to reduce its seroprevalence and related abortions. Precolostrum blood samples were collected from 52 calves and their dams. Additionally, 22 female calves were also sampled at regular 3 month intervals until 18-22 months. N. caninum specific antibodies were assayed by IFAT. Serum samples were tested at a dilution 1:25 for calves before colostrum intake and heifers before mating and 1:100 for multiparous cows. Only serum samples from IFAT seropositive cattle involved in the evaluation of the routes of transmission were assessed by a commercial IgG avidity ELISA. Seropositive cows or heifers were artificially inseminated with semen from Hereford bulls. The progenies from these female animals were sent to a feed lot to produce meat. Different generalized linear models (GLM) were used to study the relationship between abortion, age category and serostatus. Seropositive heifers were more likely to have a record of abortion (OR 2.7; 95% CI 1.6-4.7). Vertical transmission frequency was 55.5% (5 seropositive calves/9 seropositive cows). Horizontal transmission was 22.7% (5 female calves seroconverted at least one time/22 females calves sampled during 24 months) and these 5 female calves had low avidity. In heifers, both seroprevalence and abortion rates decreased from 22.1 and 8.4% of 475 in 2009 to 6.1 and 4.3% of 578 in 2015, respectively (p<0.01). Over five years, N. caninum-seroprevalence and the related abortions in heifers decreased after the control strategy was assessed.