240 EFFECTS OF REPEATED SUPEROVULATION ON EMBRYO YIELDS IN SOME TURKISH NATIVE GOAT BREEDS

Abstract

The Angora, Kilis, Honamli, Hair, and Norduz are native goat breeds in Turkey and are currently in danger of extinction. This study aimed to assess the efficacy of the repeated administration of a superovulatory (SOV) protocol for in vivo embryo production in these breeds. A total of 14 Angora, 15 Kilis, 10 Honamli, 10 Hair, and 9 Norduz goats were used in this work. The synchronization procedure was started on Day 5 after visible oestrus by using controlled internal drug release dispensers (CIDR^®) for 11 days. Administration of FSH (Folltropin^®) began on Day 9 (twice daily) and continued for 3 days (total dose: 200 mg; 50 mg × 2.30 mg × 2.20 mg × 2). A dose of prostaglandin F_2α (1.6 mg; Dalmazin^®) was injected together with first FSH injection. Gonadotropin-releasing hormone (Receptal^®: 100 µg) was injected 6 h before mating. All goats in oestrus were naturally mated twice a day for 3 days. Ovarian examination (number of corpora lutea) and embryo recovery were performed by laparotomy on Day 6 after CIDR^® withdrawal. Each uterine horn was flushed, and the embryos were recovered and counted. To avoid intra-abdominal adhesions, a 2.5% heparin solution was used during flushing. The SOV procedure was repeated once per year during the breeding season (2009 to 2011). Fertilization and recovery rates were calculated. Differences in the SOV response and embryo yields were evaluated by Friedman’s test. In Hair goats, the number of corpora lutea decreased significantly (P < 0.05) during the third SOV cycle (12.7 ± 6.2, 14.0 ± 9.1, and 6.8 ± 5.6, respectively, for cycles 1, 2, and 3), whereas no effect of the cycle was observed in the remainder of breeds. The number of expanded blastocysts increased considerably during the third cycle in Angora (0, 0.2 ± 0.8, and 1.4 ± 2.9, respectively, for cycles 1, 2, and 3), Kilis (0.2 ± 0.4, 0.3 ± 1.3, and 4.2 ± 5.0), and Honamli (0, 1.3 ± 1.7, and 3.6 ± 4.5) goats, whereas a significant decrease was observed in Norduz goats (2.4 ± 5.0, 1.8 ± 2.0, and 0.1 ± 0.3; P < 0.05). The mean numbers of unfertilized oocytes were found to be significantly increased in Angora (0.4 ± 1.6, 0, and 2.1 ± 4.1, respectively, for cycles 1, 2, and 3), Kilis (0, 1.3 ± 3.9, and 3.1 ± 5.2), and Honamli (0, 4.9 ± 5.2, and 4.5 ± 7.8) goats (P < 0.05). As a result, fertilization rates (%) showed a decrease in Angora (50, 100, 24.5, respectively, for cycles 1, 2, and 3) and Honamli (100, 42.5, and 56.3) goats (P < 0.05), whereas recovery rates showed no difference among the different breeds. The methodology presented in this study was found to be an efficient technique for superovulation of the Angora, Kilis, and Honamli goats. Because Hair and Norduz are relatively small breeds, the dosage of FSH might have had a negative effect on the superovulation and embryo yield. Additionally, the use of intra-abdominal washing solutions for preventing adhesions as observed in previous works (data not shown) is believed to have a positive effect on achieving high levels of efficiency in in vivo embryo production.