Although Schistosomus Reflexus may be seen in sows, does and ewes it is most common in cattle. The calves appear to have developed inside out. The head usually lies near the sacrum because of a marked ventral curvature of the spine.
If pregnancy is quite advanced there is a high probability of dystocia because the limbs of a schistosomus reflexus are usually ankylosed and rigid. Fetotomy to reduce the size of fetal part may allow for vaginal delivery.
Two-headed Fetal Monster
A fetus dicephalus with two heads may result in a dystocia. Fetotomy to remove the body part that is obstructing the pelvic canal may allow for a vaginal delivery.
Amorphus globosus is a skin and hair covered round structure that contains fat, connective tissue and alter soft tissue and occasional cartilage and bone. They are thought to be imperfect zygote and are parasitic on the placenta of a normal twin.
Cyclopia or cynocephalus is most commonly seen in sheep and pigs but has been seen in all of our domestic livestock. The defect can range from a single apparently normal globe to all degrees of development of one or two globes. The nose is usually absent or rudimentary and does not communicate with the pharynx. The eyelids are absent or rudimentary. The mandible tends to be elongated and the cranial end curves dorsally. The skull is small.
A calf with anasarca may be prone to dystocia because the generalized edema will cause the calf to not fit through the pelvic canal. This is a heritable condition in Ayrshire and Swedish lowland cattle. It is thought to be inherited as an autosomal recessive trait.