292 EFFECT OF A SINGLE INJECTION OF FSH DISSOLVED IN POLYETHYLENE GLYCOL ON SUPEROVULATION RESPONSE IN KOREAN NATIVE COWS

Abstract

Superovulation in bovine is usually achieved after several FSH injection in a time-consuming protocol, and the half-life of FSH is very short. This study was carried out to assess the efficiency of embryo production after induction of superovulation with a single injection of FSH (Folltropin-V, Vetrepharm, Canada) dissolved in polyethylene glycol (PEG, 8000 MW, Sigma-Aldrich Corp., St. Louis, MO, USA) in Korean Native cows. Eighty-eight cows were randomly assigned to one of four groups. In Group 1 (control), cows were intramuscularly treated with twice-daily administration of 50 mg FSH for 4 days. In Group 2 and 3, cows received a single subcutaneous injection of 400 mg and 200 mg FSH dissolved in 30% PEG, respectively. In Group 4, cows received a single subcutaneous injection of 200 mg FSH dissolved in 30% PEG given seven days after CIDR insertion. On days 10 to 12 after observed estrus, superovulation was started. Luteolysis was induced by administration of 25 mg of PGF2α (Pharmacia, Puurs, Belgium) IM 2 days after the start of the FSH injection. Donors were timed-inseminated with frozen–thawed semen at 48 and 60 h after the administration of PGF2α. Embryos were collected by non-surgical methods on 7 days after the second AI. The numbers of corpus lutea (CL), total ova, transferable embryos, and progesterone concentration were analyzed by General Linear Models Procedure with the Statistical Analysis System (SAS; SAS Institute, Inc., Cary, NC, USA) and means were compared with the Duncan’s multiple range test. Data on the pregnancy rate was analyzed by chi-square test. P values <0.05 were considered to be significantly different. The number of CL in Group 2 was significantly (P < 0.05) higher compared to Groups 1, 3 and 4 (18.5 ± 7.5 v. 11.2 ± 5.1, 13.1 ± 5.1 and 13.9 ± 6.4, respectively). However, the number of total ova (7.9 ± 6.0 to 10.4 ± 7.2) and transferable embryos (3.7 ± 3.3 to 4.7 ± 3.9) did not differ among treatment groups. In addition, blood progesterone concentrations at embryo recovery did not differ among all groups (10.0 ± 3.5 ng mL^–1 to 15.7 ± 3.2 ng mL^–1). No difference was observed among groups in pregnancy rate after transferring the recovered embryos (36.0 to 50.0%). In conclusion, our results show that a single injection of FSH dissolved in polyethylene glycol is an efficient and simple procedure for inducing superovulation in Korean native cows.