Local Component of Utero-Ovarian Relationships in the Ewe

The effects of unilateral ovariectomy and unilateral hysterectomy, alone and in ipsilateral and contralateral combinations on the life span of the corpus luteum, were studied in 44 whitefaced yearling ewes. Unilateral ovariectomy alone had no effect on estrual cycle length. Unilateral hysterectomy, whether alone or in combination with unilateral ovariectomy, consistently prolonged the life span of corpora lutea on an ipsilateral ovary and consistently failed to affect corpora lutea on a contralateral ovary. Retraction of the remaining uterine horn or ligation of the blood vessels supplying its anterior portion, in ewes unilaterally ovariectomized and unilaterally hysterectomized on the same side, gave equivocal results, but some ewes in each group showed an increased luteal life span. Prolonged luteal maintenance on the ovary adjacent to a removed uterine horn and unilateral luteal regression in the opposite ovary were observed in one ewe which had corpora lutea on each ovary.