162 Simplification of a superovulation protocol using FSH and equine chorionic gonadotrophin in beef donors
J. Carvajal Basto A , A. Catube A , A. Tribulo A , R. Tribulo A and G. A. Bo A BA Instituto de Reproduccion Animal Cordoba (IRAC), Paraje Pozo del Tigre, Gral. Paz, Cordoba, Argentina
B Instituto A.P. de Ciencias Básicas y Aplicadas, Universidad Nacional de Villa María, Villa del Rosario, Cordoba, Argentina
Reproduction, Fertility and Development 34(2) 319-319 https://doi.org/10.1071/RDv34n2Ab162
Published: 7 December 2021
© 2022 The Author(s) (or their employer(s)). Published by CSIRO Publishing on behalf of the IETS
The objective of this study was to evaluate an alternative superovulation protocol in which the last 4 FSH injections are replaced with a single injection of equine chorionic gonadotrophin (eCG). Forty-eight beef donors (body condition score 3 to 4.5; 1 to 5 scale) were superstimulated twice, with a 40-day interval in a crossover design (all donors received two treatments, which were represented equally in each replicate). On Day 0, donors received a vaginal device with 1.2 g of progesterone (Diprogest 1200, Zoovet) and 50 mg of progesterone plus 5 mg of oestradiol-17β (Laboratory Rio de Janeiro) intramuscularly (IM). On Day 4, donors in the FSH group received 8 applications of FSH (Folltropin, Vetoquinol) in twice-daily decreasing dosages over 4 days. The total dosages were 320 mg in Bonsmara cows (n = 13), 260 mg in Bonsmara and Angus heifers (n = 11) and Brangus cows (n = 21), and 140 mg in Brangus heifers (n = 3). Donors in the FSH+ eCG group received only the first four applications of Folltropin (i.e. 220 mg in Bonsmara cows, 200 mg in Bonsmara and Angus heifers and Brangus cows, and 80 mg in Brangus heifers) and 600 IU IM of eCG (Novormón, Zoetis) on Day 6. All donors also received 150 μg of D + cloprostenol (Ciclar, Zoovet) IM twice, 12 h apart on Day 6 and vaginal devices were removed on Day 7. On Day 8, donors received 20 μg of buserelin (Gestar, Over) and were inseminated 12 and 24 h later. On Day 15, ova/embryos were collected and evaluated according to the IETS standards. Data were analysed using the GLMM procedure for a Poisson distribution. The fixed variables were treatment (FSH vs. FSH+ eCG), biotype (Bos indicus vs. Bos taurus), breed (within biotype), and category (cows vs. heifers) and their interactions. The endpoints evaluated were number of coprora lutea (CL) and anovulated follicles (counted by ultrasonography), total number of ova/embryos collected, fertilised ova, and transferable embryos. There was no effect of category or breed (within biotype) in any of the endpoints evaluated, but there was a treatment by biotype interaction (P < 0.05) in all endpoints (Table 1). The interaction was attributed to greater (P < 0.05) numbers of CL and embryos and fewer (P < 0.05) unovulated follicles in the Bos indicus donors treated only with FSH. Conversely, results did not differ in Bos taurus donors, suggesting that the last four injections of FSH can be replaced by a single administration of 600 IU eCG. However, the eCG treatment resulted in decreased embryo production and increased numbers of unovulated follicles in Bos indicus donors, suggesting that a dosage of 600 IU of eCG may be too high for this biotype.
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