Department of Large Animal Sciences, Faculty of Life Sciences, University of Copenhagen, Frederiksberg C, Denmark.
Acta Vet Scand. 2011 Dec 2;53(1):64. doi: 10.1186/1751-0147-53-64.
Coxiella burnetii is a well-known cause of placentitis and subsequent abortion in ruminants, but there are no reports on the relationship with perinatal mortality. The study was performed to determine the influence of level and change of bulk tank milk (BTM) antibodies to C. burnetii on two outcomes associated with parturition in cattle: a) stillbirth; and b) stillbirth and neonatal mortality combined (perinatal death).
Twenty-four Danish dairy herds were tested repeatedly for antibodies to C. burnetii in BTM using a commercial ELISA. Samples were collected monthly from July 2008 to July 2009. Information on the 2,362 calvings occurring in the study period was obtained from the Danish Cattle Database. Two multilevel logistic regression models were created for the two outcomes stillbirth and perinatal mortality. One model included the level of BTM antibodies in a specified period before or after the outcome had occurred. The other model included the change in antibodies over time. These predictors were included both at herd and animal level. Furthermore, all models included parity and breed.
The individual monthly BTM antibody levels were highly correlated within herds. Consequently, changes in BTM antibody levels were not found to be associated with neither risk of stillbirth nor the risk of perinatal mortality. However, the risk of stillborn calves and perinatal death was higher with high level of BTM antibodies 8 to 9 months after the incident, but not outside this period.
We conclude that the level of antibodies to C. burnetii in BTM may be associated with perinatal mortality, but the association was not persistent and should be investigated further.
贝氏考克斯氏体是引起反刍动物胎膜炎和随后流产的已知原因，但尚无关于其与围产期死亡率关系的报道。本研究旨在确定牛分娩相关两种结局（a）死产；和（b）死产和新生儿死亡合并（围产死亡）与牛批量奶（BTM）中抗贝氏考克斯氏体抗体水平和变化的关系。
使用商业 ELISA 对 24 个丹麦奶牛场的 BTM 中的抗贝氏考克斯氏体抗体进行了反复检测。从 2008 年 7 月至 2009 年 7 月，每月采集一次样本。从丹麦牛数据库中获得了研究期间发生的 2362 次分娩的信息。为两种结局死产和围产死亡创建了两个多层次逻辑回归模型。一个模型包括在结果发生前后特定时期内 BTM 抗体的水平。另一个模型包括抗体随时间的变化。这些预测因子均在畜群和动物水平上进行了包括。此外，所有模型均包括胎次和品种。
单个月度 BTM 抗体水平在畜群内高度相关。因此，BTM 抗体水平的变化与死产风险或围产死亡风险无关。然而，在事件发生后 8 至 9 个月，BTM 抗体水平高与死产小牛和围产死亡的风险增加有关，但在此期间之外则没有。
我们得出结论，BTM 中抗贝氏考克斯氏体抗体的水平可能与围产死亡率有关，但这种关联并不持久，应进一步研究。
