AVALIATION OF EMPLOYING THE MODIFIED OVSYNCH PROTOCOL ON PREGNANCY RATE AND FETAL MORTALITY IN BUBALUS BUBALIS

Abstract

This experiment aimed to evaluate the use of luteinizing hormone (LH) and human chorionic gonadotropin (hCG) in replacement to gonadotropin-releasing hormone (GnRH) in estrus synchronization protocols in female buffalo, in order to artificial insemination at fixed time (TAI), verify the influence of body condition score (BCS), on pregnancy rates of each group and assess the overall rate of fetal mortality. We used the traditional Ovsynch protocol in Group 1 (G1) with modifications in G2 and G3 (GnRH = D0, D7 = D9 = PGF2 and GnRH, hCG or LH, respectively), to synchronize estrus of 106 buffaloes of Murrah and Mediterranean during the breeding season of 2008. In D9 protocol the animals were randomly divided into three groups and received: GnRH (G1) - (lecirelin acetate 25μg, n = 38), hCG (G2) - (2500 IU, n = 35) or LH (G3) - (12.5 mg, n = 33). After 16 hours (16 hours + D9), held on TAI and measured the diameter of the preovulatory follicle with ultrasound examinations. Pregnancy diagnosis was performed on day 43 after TAI, and repeated on day 61 in order to check the fetal mortality rate. The conception rates between the groups GnRH, hCG and LH, were respectively: 39.4, 51.4 and 45.5% (p> 0.05); ultrasound done on the day of TAI revealed that 90.4% of animals had pre-ovulatory follicles of 11.9 mm in diameter in the ovaries, hCG and LH groups had a higher pregnancy rate than the GnRH group (p> 0.05). The fetal mortality rate was 6.25%. Comparing the ECC with pregnancy rates in G1, G2 and G3, there was no difference (p> 0.05). It is concluded that there was no significant difference between treatments and that the fetal mortality rate can be reduced with the improvement of ECC animals.