Field synchronization of Ethiopian Highland sheep for fixed time artificial insemination: improvement of conception rate with a double injection of prostaglandin at 11 days

• Main Authors: Shanbel Besufkad, Simret Betsha, Chekol Demis, Tesfaye Zewude, Mariem Rouatbi, Tesfaye Getachew, Aynalem Haile, Barbara Rischkowsky, Mourad Rekik
• Format: Article
• Language: English
• Published: Taylor & Francis Group 2020-01-01
• Series: Journal of Applied Animal Research
• Subjects: menz sheep; artificial insemination; synchronization; prostaglandins; conception rate
• Online Access: http://dx.doi.org/10.1080/09712119.2020.1815752
• ISSN: 0971-2119; 0974-1844

The study investigated, for fixed time artificially inseminated (AI) Menz ewes in field trials, the reproductive performance of prostaglandin-based treatments simultaneously to the standard ‘P4+eCG’ protocol. A total of 483 Menz ewes were assigned to either the ‘P4+eCG’ protocol, using progesterone impregnated intravaginal sponges in combination with equine chorionic gonadotropin (eCG) injection at sponge withdrawal, or the ‘PGFs’ treatment where sheep received a single injection of prostaglandin or ‘PGF7’ and ‘PGF11’ where ewes were synchronized with 2 injections of prostaglandin 7 or 11 days apart, respectively. AI was implemented with fresh semen at 55 ± 1 h after the end of the hormonal treatment. Conception rate (CR; 60.87 ± 4.2) was highest for PGF11 ewes (P < 0.05); PGFs ewes had the lowest CR (34.07 ± 4.1). Other factors did not affect variation in CR (P > 0.05). A higher proportion of ewes in the P4+eCG group yielded twins and triplets compared to the 3 prostaglandin-based protocols (P < 0.01). Nevertheless, a higher (P = 0.02) proportion (17.11 ± 4.3) of PGF11 ewes yielded twins by comparison to their PGF7 counterparts (2.50 ± 2.5). PGF-based protocol with 2 injections 11 days apart, preceded by a careful selection of non-pregnant ewes for cervical fixed-time AI, is a feasible reproductive management for sheep breeding programmes in Ethiopia.