Observation of uterine endometrium in the postpartum cows by scanning electron microscope

Five postpartum Chinese-Holstein cows were used to monitor the changes of the uterine endometrium by scanning electron microscope.The results showed that during the early stage postpartum,some parts of the endometrium were damaged and the adjacent tissues to the endometrium were necrotic and exfoliated during the first 7 days pospartum.The pili and microvilli on the appeared normal epithelial cells were also damaged and markedly reduced in their number.By the second week after parturition the basal cells under the pseudostratified columnar epithelium of the uterine endometrium started to grow towards the uterine lumen to repair the damaged uterine epithelium.By the fourth week after calving the area of the damaged uterine endometrium were getting smaller.The pili and microvilli increased in their number with a regulation in shape.It was observed that a few epithelial cells lost by the day 45 postpartum and by the day 60 postpartum the endometrium of the uterus were all covered by epithelial cells with regular pili and microvilli.The results indicated that reparation of the uterine endometrium in the postpartum cows was completed within 60 days after calving.