Successful pregnancy in estrus-synchronized Himalayan tahrs (Hemitragus jemlahicus) by transcervical insemination

Assisted reproductive technologies have not been widely applied to Himalayan tahrs (Hemitragus jemlahicus), a Near Threatened species, despite increasing concerns over population management and conservation. Developing effective estrus synchronization and artificial insemination protocols is critical for their reproductive management.

To evaluate the effectiveness of transcervical insemination using extended-fresh (EF) and extended-chilled (EC) semen following estrus synchronization using controlled internal drug release (CIDR) and hormonal treatments in female Himalayan tahrs.

This study involved eight female Himalayan tahrs, which were divided into two treatment groups of 13-day and 15-day according to duration of CIDR insertion. Hormonal treatments including pregnant mare serum gonadotropin, human chorionic gonadotropin, and prostaglandin F2 alpha (PGF_2α) were administered. Semen was collected from two males by electroejaculation, extended, and used either fresh, frozen-thawed, or chilled. Transcervical insemination was performed at fixed times after CIDR removal, and pregnancy was diagnosed 64 days post-insemination using Doppler ultrasonography.

Three of four females in the 13-day group and one of four in the 15-day group were confirmed pregnant. Vaginal and cervical changes were more favorable for insemination in the 13-day group. Hormonal data supported that a sharp drop in progesterone after CIDR removal was associated with successful conception.

Thirteen-day CIDR insertion combined with gonadotropins and PGF_2α is effective for estrus synchronization in Himalayan tahrs. Transcervical insemination using EF and EC semen resulted in successful pregnancy, offering a practical and reproducible protocol for ex situ conservation breeding in this species.