Impact of spontaneous Neospora caninum infection on pregnancy loss and subsequent pregnancy in grazing lactating dairy cows

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• 作者：Gilson Antonio Pessoap>ap>p> ; p>p>bp>p> ; p>p>gilsonpessoavet@yahoo.com.br" class="auth_mail" title="E-mail the corresponding authorp> ; Ana Paula Martinip>bp> ; Janislene Mach Trentinp>ap> ; Vanessa Calderaro Dalcinp>cp> ; Carlos Eduardo Porciuncula Leonardip>bp> ; Fernanda Silveira Flô ; res Vogelp>dp> ; Manoel Francisco de Sá ; Filhop>bp> ; Mara Iolanda Batistella Rubinp>bp> ; Carlos Antonio Mondino Silvap>bp>
• 关键词：Abortion ; Dairy cow ; Reproduction ; Neosporosis ; Uterine disease
• 刊名：Theriogenology
• 出版年：2016
• 出版时间：February 2016
• 年：2016
• 卷：85
• 期：3
• 页码：519-527
• 全文大小：662 K

文摘

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. Seropostive 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 &plusmn; 0.3 L/day) than in SN cows (24.8 &plusmn; 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.