Fertility obtained with different progestogen intravaginal devices using Short-term protocol for fixed-time artificial insemination (FTAI) in sheep

The objective of this study was to evaluate the pregnancy outcomes obtained with either cervical or intrauterine insemination after Short-term protocols (6 days) for FTAI comparing different progestogens and intravaginal devices in sheep. Two experiments were performed during breeding season on a total of 883 Corriedale multiparous ewes. In the Experiment 1, 569 ewes received a Short-term protocol for 6 days in a 3 x 2 factorial design using three different intravaginal devices (DICO, CIDR-G or sponges) and two insemination techniques (cervical or intrauterine FTAI). DICO and CIDR-G devices contain 0.3 g progesterone impregnated in a silicone matrix, while polyurethane sponges contain 60 mg medroxiprogesterone acetate (MPA). The Experiment 2 was carried out on 314 ewes that received a Short-term protocol for 6 days in a 2 x 2 factorial design with two devices (DICO or CIDR-G previously used for 6 days) and two insemination techniques (cervical or intrauterine FTAI). For all the treatments in both experiments one luteolytic dose of an analog of prostaglandin F2alpha and 300 IU eCG were given at the time of device removal. For each experiment, cervical insemination (200 million of spermatozoa) or laparoscopic intrauterine insemination (100 million of spermatozoa) was performed with fresh semen at 48 or 54 h after device removal, respectively. Pregnancy diagnosis was determined by transrectal ultrasonography 40 days after insemination. In Experiment 1, total of pregnancy rate (pregnant ewes/inseminated ewes) with progesterone siliconed devices (DICO: 55.7%, 97/174; CIDR-G: 55.8%, 110/197) was greater than MPA sponges (37.4%, 74/198; P <0.05), and was lower for cervical (39.8%, 109/274) than intrauterine insemination (58.3%, 172/295; P <0.05). In Experiment 2, pregnancy rate was similar among re-used DICO (45.3%; 63/139) and CIDR-G devices (46.8%; 82/175), and was higher for intrauterine (55.0%; 88/160) than cervical insemination (37.0%; 57/154; P <0.05). For both experiments, no interaction was found between type of device and insemination technique. In conclusion, the current study shows greater pregnancy rate with both siliconed devices containing progesterone than sponges containing MPA, both by cervical and intrauterine FTAI. In addition, both siliconed devices containing 0.3 g progesterone allow similar outcomes when used twice in a Short-term protocol for 6 days. (C) 2015 Elsevier B.V. All rights reserved.