Placentation and ovulation in a ewe
Keywords: ovine, placenta, pregnancy, melanin
Image size: 2000 x 1333px
An ovine uterus that had contained a 25 day twin pregnancy. Note the melanin pigment in the caruncles; a normal finding in many sheep. Also note the early formation of caruncular attachment even though cotyledons were not yet macroscopically visible on the chorion of the fetuses. Of further interest is the fact that small pits are visible (arrow) on the caruncles; these will develop further to become deep and concave, enveloping the cotyledons. This is similar to the situation in goats but is unlike that in cattle where the cotyledons cover the caruncles instead.
There are two corpora luteal in the right ovary, showing that twin ovulation have occurred. Twin ovulations are very common in ewes, and triple ovulations are not uncommon. The presence of a fecundity gene in Baroola ewes makes multiple ovulations very common indeed. The author is aware of one case in a Dorper ewe where seven lambs were born to a single ewe that had not been pharmacologically superovulated.
