Pessoa Gilson Antonio, Martini Ana Paula, Trentin Janislene Mach, Dalcin Vanessa Calderaro, Leonardi Carlos Eduardo Porciuncula, Vogel Fernanda Silveira Flôres, de Sá Filho Manoel Francisco, Rubin Mara Iolanda Batistella, Silva Carlos Antonio Mondino
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.
Embryolab - Laboratory of Animal Embryology, Department of Large Animals-Universidade Federal Santa Maria (UFSM), Santa Maria, Rio Grande do Sul, Brazil.
Theriogenology. 2016 Feb;85(3):519-27. doi: 10.1016/j.theriogenology.2015.09.034. Epub 2015 Sep 26.
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.
评估了犬新孢子虫自然感染对放牧泌乳奶牛流产及后续妊娠的影响。分析了来自六个预选奶牛场的1273头母牛（878头经产母牛和395头初产母牛）的数据。通过间接免疫荧光法检测抗犬新孢子虫抗体，将母牛分为血清阳性（SP）（患病率24%；范围11%-33%）或血清阴性（SN）。血清阳性母牛（患病率40.0%）的流产发生率高于血清阴性母牛（患病率4.1%）（P<0.001）。通过实时聚合酶链反应在44.4%的血清阳性母牛完整流产胎儿中检测到犬新孢子虫DNA，而血清阴性母牛流产胎儿中未检测到。调整至305天的平均日产奶量，血清阳性母牛（22.5±0.3升/天）低于血清阴性母牛（24.8±0.2升/天）（P<0.001）。此外，血清阳性母牛胎盘滞留发生率更高（17.1%对6.0%；P<0.001），急性产后子宫炎发生率更高（9.8%对2.4%；P<0.001）。尽管首次产后人工授精后的妊娠率相似（27.6%对31.8%；P = 0.40），但血清阴性母牛在产奶300天内的累积妊娠率更高（94.7%对98.5%；P = 0.005）。与血清阴性母牛相比，血清阳性母牛在产奶300天时的Cox妊娠率比例风险降低（P = 0.0001），从分娩或流产到受孕的间隔时间更长（中位数，111天对101天）。犬新孢子虫自然感染是导致流产和子宫疾病（即胎盘滞留和子宫炎）发生的重要因素，对放牧泌乳奶牛的后续妊娠产生负面影响。
