During parturition, to deliver a healthy lamb, the collagen of the cervix, uterus, vagina and pelvic ligaments must soften to decrease the resistance through the cervix and vagina.
Caesarean section is the most effective method of delivering a healthy lamb if dystocia occurs.
The term used to describe when the cervix does not dilate during parturition is ringwomb. The specific cause of ringwomb is not known but may be due to a lack of release of hormones involved in softening collagen or a lack of response of the collagen in the cervix to hormonal stimulation. Mineral deficiency, malpresentation, premature lambing, and consumption of feedstuffs that contain estrogen do not cause ringwomb. There is no correlation of ringwomb with breed of sheep, age, and body condition score. Clinical Signs of Ringwomb Unlike normal ewes, ewes with ringwomb do not isolate themselves or have a decreased appetite during the first-stage of labor.