Adventitious placentation in a cow.
Keywords: placenta, adventitious, placentitis, bovine, cow, infertility
Small to large irregular placentome-like structures may develop on the placenta adjacent to normal placentomes. These have been referred to as "adventitious" placentomes and the condition itself as "adventitious placentation. The word adventitious is derived from the Latin meaning "coming from outside" but in zoology, it refers to something that is in an unusual position or place. The adventitious placentomes may be localized or spread throughout the allantochorion/endometrium.
It is often stated that adventitious placentation is associated with hydrops conditions but it may occur in seemingly normal pregnancies. However, when adventitious placentation is obvious, one should probably consider the placenta and uterus as a unit and cull the cow because of the potential for infertility.