Comparative efficacy of G6G and Ovsynch protocols on synchronization and pregnancy rate in Nili-Ravi buffalo

The aim of this work was to evaluate the efficacy of G6G and Ovsynch protocols on synchronization and pregnancy rate in Nili-Ravi buffalo. For this, a total of fifty buffalo were assigned into two treatment groups: (1) G6G (n = 25) and (2) Ovsynch (n = 25). The blood samples were collected from all the treated buffalo on day (D) 7 (PGF(2 alpha) injection of Ovsynch) to measure the progesterone (P-4). All the buffalo were fixed time inseminated (FTAI) following last GnRH of Ovsynch. Ultrasonography was performed for follicular, corpus luteum (CL) dynamics and pregnancy diagnosis. The results revealed that synchronization rate and response to final PGF2a were significantly (P < 0.05) higher in G6G compared to Ovsynch. The ovulation to first GnRH of Ovsynch was higher (P< 0.05) in G6G (84%) than Ovsynch (56%). The mean dominant follicle size following last GnRH of Ovsynch showed significantly larger diameter in G6G (11.7 +/- 0.2 mm) compared to Ovsynch (10.9 +/- 0.2 mm). Moreover, the higher (P < 0.05) P4 concentration was observed in G6G than Ovsynch. The presence of double CL on D 7 was higher (P < 0.05) in G6G (64%) than Ovsynch (24%) group. The pregnancy rate (P = 0.08) tended to be greater in G6G compared to Ovsynch. In conclusion, G6G treatment showed better ovulatory and luteolytic response to first GnRH and PGF(2 alpha) compared to Ovsynch treatment. Moreover, the addition of GnRH and PGF(2 alpha) prior to Ovsynch is helpful to improve synchronization application of Ovsynch protocol in Nili-Ravi buffalo. (C) 2015 Elsevier B.V. All rights reserved.