title: Impact of spontaneous Neospora caninum infection on pregnancy loss and subsequent pregnancy in grazing lactating dairy cows.
abstract: The impact of spontaneous Neospora caninum infection on pregnancy loss and subsequent pregnancy in grazing lactating dairy cows was evaluated. Data from 1273 females (878 multiparous and 395 first-calving cows) from six preselected dairy herds were analyzed. Cows were classified as seropositive (SP) (prevalence, 24%; range, 11%-33%) or seronegative (SN) by indirect immunofluorescence detection of antibodies against N caninum. Seropositive cows (prevalence, 40.0%) presented higher (P < 0.001) incidence of abortion compared with SN cows (prevalence, 4.1%). Neospora caninum DNA was detected by real-time polymerase chain reaction in 44.4% of intact aborted fetuses from SP cows, whereas none was found in those aborted from SN cows. The average daily milk production adjusted to 305 days was lower (P < 0.001) in SP (22.5 ± 0.3 L/day) than in SN cows (24.8 ± 0.2 L/day). Furthermore, SP cows presented greater occurrence of retained placenta (17.1% vs. 6.0%; P < 0.001) and acute postpartum metritis (9.8% vs. 2.4%; P < 0.001). Despite similar pregnancy rates after first postpartum artificial insemination (27.6% vs. 31.8%; P = 0.40), cumulative pregnancy rates during 300 days in milk (94.7% vs. 98.5%; P = 0.005) were greater in SN cows. A reduced (P = 0.0001) Cox proportional hazard of pregnancy rate at 300 days in milk and a longer interval from parturition or abortion to conception (median, 111 vs. 101 days) were observed in SP compared with SN cows. Spontaneous N caninum infection is a significant contributing factor of pregnancy loss and occurrence of uterine disease (i.e., retained placenta and metritis), negatively affecting subsequent pregnancy in grazing lactating dairy cows.
authors.affiliation: Graduate Program in Animal Medicine: Equine, Universidade Federal do Rio Grande do Sul (UFRGS), Porto Alegre, Rio Grande do Sul, Brazil; Embryolab - Laboratory of Animal Embryology, Department of Large Animals-Universidade Federal Santa Maria (UFSM), Santa Maria, Rio Grande do Sul, Brazil. Electronic address: gilsonpessoavet@yahoo.com.br.
authors.forename: Gilson Antonio
authors.initials: GA
authors.lastname: Pessoa
authors.affiliation: Embryolab - Laboratory of Animal Embryology, Department of Large Animals-Universidade Federal Santa Maria (UFSM), Santa Maria, Rio Grande do Sul, Brazil.
authors.forename: Ana Paula
authors.initials: AP
authors.lastname: Martini
authors.affiliation: Graduate Program in Animal Medicine: Equine, Universidade Federal do Rio Grande do Sul (UFRGS), Porto Alegre, Rio Grande do Sul, Brazil.
authors.forename: Janislene Mach
authors.initials: JM
authors.lastname: Trentin
authors.affiliation: Veterinary of the Agricultural, Department of the State Government of Rio Grande do Sul, Brazil.
authors.forename: Vanessa Calderaro
authors.initials: VC
authors.lastname: Dalcin
authors.affiliation: Embryolab - Laboratory of Animal Embryology, Department of Large Animals-Universidade Federal Santa Maria (UFSM), Santa Maria, Rio Grande do Sul, Brazil.
authors.forename: Carlos Eduardo Porciuncula
authors.initials: CE
authors.lastname: Leonardi
authors.affiliation: Department of Preventive Veterinary Medicine, UFSM, Santa Maria, Rio Grande do Sul, Brazil.
authors.forename: Fernanda Silveira Flôres
authors.initials: FS
authors.lastname: Vogel
authors.affiliation: Embryolab - Laboratory of Animal Embryology, Department of Large Animals-Universidade Federal Santa Maria (UFSM), Santa Maria, Rio Grande do Sul, Brazil.
authors.forename: Manoel Francisco
authors.initials: MF
authors.lastname: de Sá Filho
authors.affiliation: Embryolab - Laboratory of Animal Embryology, Department of Large Animals-Universidade Federal Santa Maria (UFSM), Santa Maria, Rio Grande do Sul, Brazil.
authors.forename: Mara Iolanda Batistella
authors.initials: MI
authors.lastname: Rubin
authors.affiliation: Embryolab - Laboratory of Animal Embryology, Department of Large Animals-Universidade Federal Santa Maria (UFSM), Santa Maria, Rio Grande do Sul, Brazil.
authors.forename: Carlos Antonio Mondino
authors.initials: CA
authors.lastname: Silva
mesh_terms: D000034:Abortion, Veterinary / Q000469:parasitology*; D000818:Animals; D000913:Antibodies, Protozoan / Q000097:blood; D002417:Cattle; D002418:Cattle Diseases / Q000469:parasitology*; D003048:Coccidiosis / Q000662:veterinary*; D004716:Endometritis / Q000469:parasitology / Q000662:veterinary; D005260:Female; D007774:Lactation; D018688:Neospora / Q000276:immunology; D018457:Placenta, Retained / Q000469:parasitology / Q000662:veterinary; D011247:Pregnancy; D015597:Pregnancy Complications, Parasitic / Q000662:veterinary*; D012098:Reproduction
chemical_list: D000913:Antibodies, Protozoan
keywords: Abortion; Dairy cow; Neosporosis; Reproduction; Uterine disease