NAVLE（北美执业兽医考题）Day 752

An owner brings her 4-year old female Labrador Retriever to your clinic because she believes she might be pregnant. She does not remember when the dog's last heat cycle was. The dog's abdomen appears fairly distended and you take a lateral abdominal radiograph which is shown below. What would be the earliest time you would expect to be able to see fetal skeletons on abdominal radiographs in the dog?
主人把他4岁的拉布拉多犬带来看诊因为她相信她的狗怀孕了。她不记得这只狗最近一次发情的时间。这只狗的腹壁坚实，腹围增大，你为她拍摄的腹部X光片如下图所示。你能在X光片上看到这只狗腹中胎儿的骨骼的最早妊娠时间是多久？