The cervix opening feels like a hardened rubber ring containing the cervical muscles that relax during normal birth. As the muscles relax, they stretch and there is enough expansion to allow a lamb to enter the birth canal. With this condition, the cervix will not open.
Ringwomb. Failure of the cervix to dilate is called "ringwomb." It is one of the most difficult lambing problems to deal with. True ringwomb does not usually resond to any medical treatment or to gentle manipulation of the cervix. A caesarian section is usually the only option. Ewes experiencing ringwomb should probably be removed from the flock. Ringwomb occurs most commonly in ewe lambs. Selenium deficiency is considered to be a contributing factor, but the condition is not fully understood. Its exact cause is unknown.