Each puppy emerges in its own placental membrane, or sac, which must be removed before the puppy can breathe.
胎衣包裹住犬仔，在犬仔呼吸之前，就要将胎衣去掉。The mother usually takes care of this by tearing off (and sometimes eating) the membrane, and then severs the umbilical cord.
母犬也通常会将胎衣撕开（有时是吃掉），然后咬断脐带。You must take over if the bitch neglects to remove a sac or sever an umbilical cord.
如果母犬没有扯掉胎衣或者是咬断脐带，主人就要接手母犬的工作。Treatment of placental retention by the combination of traditional Chinese medicine and West medicine
中西结合治疗奶牛胎衣不下The Relationship Between Afterbirth Non-exuviation of Chinese Holstein Cows and the Contents of Progesterone and Oestradiol in Their Milk
奶牛胎衣不下与乳中孕酮、雌二醇含量的关系The Curative Effect of Dairy Cows'Retained Fetal Membranes by Injecting Chinese Traditional Medicine into Point
中药穴位注射对奶牛胎衣不下的疗效观察Preventing Retention of Fetal Membranes of Dairy Cows by Chinese Traditional Medicine
中药防滞灵防治奶牛胎衣不下试验Influence of Serum Calcium, Phosphorus and Glucose Level on Retention Fetal Membrane of Dairy Cows
血清钙、磷和葡萄糖水平对奶牛胎衣不下的影响A Brief Discussion on the Pathogeny, Prevention and Treatment of Retained Fetal Membrane
浅谈奶牛胎衣不下的病因及防治体会