130 Effect of adding equine chorionic gonadotrophin to two-dose cloprostenol synchronisation protocol on reproductive parameters in cyclic goats
L. Côrtes A D , G. Vergani B , J. Rodrigues A , R. Batista C , B. Waddington A , J. Souza-Fabjan C and J. Fonseca DA Universidade Federal de Viçosa, Viçosa, Minas Gerais, Brazil
B Universidade Estatual Paulista, Jaboticabal, São Paulo, Brazil
C Universidade Federal Fluminense, Niterói, Rio de Janeiro, Brazil
D Embrapa Caprinos e Ovinos, Coronel Pacheco, Minas Gerais, Brazil
Reproduction, Fertility and Development 35(2) 192-193 https://doi.org/10.1071/RDv35n2Ab130
Published: 5 December 2022
© 2023 The Author(s) (or their employer(s)). Published by CSIRO Publishing on behalf of the IETS
The objective of the present study was to analyse the effect of adding equine chorionic gonadotrophin (eCG) to the cloprostenol-based synchronisation protocol on reproductive parameters in cyclic goats undergoing nonsurgical embryo recovery (NSER) and verify the feasibility of NSER without the use of cervical-relaxation drugs. Therefore, 24 cyclic goats had oestrous synchronised with two 125 µg doses of cloprostenol (Sincrocio®, Ourofino) latero-vulvar at 7.5-day interval and received 100 IU of eCG (GE; n = 12) (Novormon®, Zoetis) or 0.5 mL of saline (GS; n = 12) i.m. along with the second dose of cloprostenol. The first dose was administered in the morning on a random day of the oestrous cycle and the second in the afternoon. Oestrous detection and mating were performed every 12 h, with fertile bucks (n = 4), starting after the application of the second dose of cloprostenol. Seven days after the first mating, NSER was performed, and the recovered structures were evaluated. The data were subjected to the Shapiro-Wilk test for normality analysis; parametric variables were analysed by Student’s t-test; nonparametric variables were analysed by Mann-Whitney test and Fisher’s exact test; P < 0.05 was considered as significant, and the results in the text are reported as means ± standard error of the mean (s.e.m.). Number of animals and total number of corpora lutea or structures or their proportions are shown in square brackets. Oestrous response rate and oestrous onset were similar (P > 0.05) between GE (91.7% [11/12] and 31.6 ± 3.3 h) and GS (91.7% [11/12] and 29.4 ± 3.3 h), respectively. Also, no difference (P > 0.05) was found for the percentage of females with corpora lutea 1 day before NSER (100% for GE and GS), number of corpora lutea per female (GE: 1.8 ± 0.2 [20] and GS: 1.9 ± 0.2 [21]), percentage of females successfully flushed (GE: 90.9% [10/11] and GS: 81.8% [9/11]) and number of corpora lutea per flushed female (GE: 1.7 ± 0.2 [17] and GS: 1.8 ± 0.2 [17]). Similar (P > 0.05) results were obtained between groups regarding the total structures recovered per flushed female (GE: 0.7 ± 0.2 [7] and 0.5 ± 0.2 [5]), unfertilised eggs per flushed female (GE: 0.0 ± 0.0 and GS: 0.2 ± 0.1), rate of viable (grades 1, 2 or 3) embryos per flushed female (GE: 0.7 ± 0.2 [7] and GS: 0.2 ± 0.1 [2]), and blastocysts (GE: 0.5 ± 0.2 [5/7] and GS: 0.1 ± 0.1 [1/2]). Goats from GE presented a greater (P < 0.05) embryo viability rate (100% [7/7]) compared to GS (40% [2/5]). We conclude that adding eCG to the last dose of cloprostenol of the 7.5-day synchronisation protocol enhances the viable embryo production. Furthermore, we were able to prove that non surgical embryo recovery can be performed without using cervical relaxation drugs in goats.
This research was supported by FAPEMIG (PPM-00201-17) and CAPES.
