Use of GnRH to induce an accessory corpus luteum in buffaloes fixed time artificially inseminated

Abstract

The objective of this study was to induce an accessory corpus luteum (CL) in buffaloes fixed time artificially inseminated. Two hundred and forty buffaloes received the treatment sequence GnRH/PGF2α/GnRH after which were inseminated artificially. Six days after the insemination, the animals were divided in two groups (G1 = Control and G2 = GnRH) and received 0 µg or 25 µg of GnRH to induce an accessory CL. After twenty four days (D40), pregnancy diagnosis was performed by ultrasonography and 79 buffalo (G1, n = 39; G2, n = 40) were randomly selected to verify the ovary status by ultrasound. Fifty three pregnant buffaloes (G1, n = 32; G2, n = 21) were followed to verify the birth rate. Data were analyzed by Chi-square test. The conception rate, the accessory CL rate and the birth rate were higher in G2 than in G1 (P<0.05). The use of GnRH to induce an accessory CL in buffaloes increased the conception and birth rates. Thus, the increase of the cost of Ovsynch protocol with the thirty dose of GnRH is rewarded by the increment on conception and birth rates and reduction of days open.