Schuijt G
Department of Herd Health and Reproduction, Faculty of Veterinary Science, State University of Utrecht, The Netherlands.
J Am Vet Med Assoc. 1990 Nov 1;197(9):1196-202.
To determine the pathogenesis of vertebral fractures in calves during the perinatal period, a retrospective study was done to determine the relationships between clinical factors at dystocia and the findings during necropsy of 235 perinatally dying calves. It was concluded that excessive traction is the most important cause of rib and vertebral fractures in the calf during dystocia. Vertebral fractures in perinatally dying calves may not be simply judged as a sign of asphyxia. The occurrence of vertebral fractures is highly correlated with the type of delivery and the force of traction. The veterinarian as well as the type of calf also are influencing factors. More perinatally dying calves were delivered after hips were locked, when extraction had been forced, or through induction of trauma when the head of the calf had the pelvic canal during the first obstetric examination. Consequently, fetal position at delivery may predispose calves to risky extractions and to the risk of perinatal death secondary to trauma. In light calves, significantly more vertebral fractures occurred during extractions than in other calves. Therefore, the veterinarian should accurately estimate the birth weight of the calf and the force of traction that should be applied.
为了确定围产期犊牛椎体骨折的发病机制，进行了一项回顾性研究，以确定难产时的临床因素与235头围产期死亡犊牛尸检结果之间的关系。得出的结论是，过度牵引是犊牛难产时肋骨和椎体骨折的最重要原因。围产期死亡犊牛的椎体骨折不能简单地判定为窒息迹象。椎体骨折的发生与分娩类型和牵引力度高度相关。兽医以及犊牛类型也是影响因素。更多围产期死亡犊牛是在臀部卡住后、强行牵拉或在首次产科检查时犊牛头位于盆腔时通过诱发创伤娩出的。因此，分娩时的胎儿位置可能使犊牛易于进行危险的牵拉，并增加因创伤导致围产期死亡的风险。在轻体重犊牛中，牵拉过程中发生的椎体骨折明显多于其他犊牛。因此，兽医应准确估计犊牛的出生体重和应施加的牵引力度。
