- Suckled Brahman crossbred cows were utilized to assess the effect of unilateral ovariectomy (UOVX) on short-term fertility. Unilateral ovariectomy via colpotomy was performed on Day 12 or 13 of a synchronized estrous cycle in 17 cows, removing the corpus luteum (CL)-bearing ovary. Four days later, cows were subdivided into three groups, each of which included 14 unoperated herdmates. Two of the groups were re-synchronized with a commercial preparation containing norgestomet and estradiol valerate (SYNCRO-MATE-B; SMB) and bred using 48-h timed artificial insemination (SMB-AI) or natural service (SMB-NS). The third group was untreated (nonsynchronized) and bred by NS. Calves were removed from all cows for 48 h beginning at SMB implant removal. All females were exposed to a fertile clean-up bull for 48 days following the synchronized breeding period. Neither estrus characteristics nor pregnancy rates differed between UOVX and UCON females. Supravaginal colpotomy is an efficient method of performing unilateral ovariectomies in the bovine and does not appear to compromise physiologic status of the remaining ovary nor to impair short-term fertility in most cows. 1989.