227 Is the antral follicle count on a random day of the oestrous cycle correlated with superovulatory responses in Santa Inês ewes?
M. Pupin A , G. Vergani A , M. Lima B , K. Silva C , A. Monteiro C , A. Ramos D , R. Batista E , W. Vicente A , M. Oliveira A and J. Fonseca CA São Paulo State University (UNESP/FCVA), Jaboticabal, SP, Brazil;
B Ceará State University (UEC), Fortaleza, CE, Brazil;
C Embrapa Goats and Sheep, Sobral, CE, Brazil;
D Embrapa Genetic Resources, Brasilia, DF, Brazil;
E Federal University of Vales dos Jequitinhonha and Mucuri, Diamantina, MG, Brazil
Reproduction, Fertility and Development 32(2) 241-242 https://doi.org/10.1071/RDv32n2Ab227
Published: 2 December 2019
Abstract
Antral follicle count (AFC) performed after an oestrus synchronization protocol has been studied as a tool to select ewes with high potential for in vivo embryo production (Pinto et al. 2018 Theriogenology 113, 146-152). However, it would be interesting to know whether AFC assessed on a random day of the oestrous cycle correlates with the superovulatory response. The present study was conducted to evaluate the correlation between AFC at the beginning of progesterone (P4)-based oestrus synchronization protocol used as basis of superovulatory treatment and the number of corpora lutea (CL) 12 h before recovery of embryos in Santa Inês ewes. The study was conducted during September and October in northeast Brazil (03°40′26″S and 40°14′20″W) using 8 adult Santa Inês ewes. On a random day of oestrous cycle (Day 0) all ewes received an intravaginal device (CIDR) of progesterone (0.3 g, Eazi-breed, Zoetis), which remained for 9 days. On Day 7, the pFSH (133 mg, Folltropin V, Vetoquinol) treatment began, with 6 decreasing doses (25, 25, 15, 15, 10, and 10%) injected IM at 12-h intervals. On Day 9, 2 equal doses of D-cloprostenol were injected at a 12-h interval (37.5 µg, Prolise, Agener União). All ewes showed oestrus and were mated by fertile rams. Flunixin meglumine (24.9 mg; Banamine, MSD Animal Health) was administered IM on Days 12, 13, and 15. On Day 16, non-surgical embryo recovery (NSER) was performed after cervical dilation using D-cloprostenol and oestradiol benzoate at 16 h and oxytocin 20 min before. Transrectal B-mode ultrasound evaluations (Z5 Vet, Mindray), frequency 7.5 MHz, were performed on Day 0 and 7 and 12 h before NSER to evaluate the ovarian population present. Pearson correlation analysis (P < 0.05) was performed using Bioestat 5.3 software. The number of AFC per ewe at the beginning of the protocol and on Day 7 were 9.9 ± 2.7 and 11 ± 3.2, respectively. The numbers of CL, recovered embryos, and viable embryos were 14.0 ± 3.5, 8.2 ± 10.9, and 6.0 ± 11.0, respectively. There was no correlation of AFC on a random day of oestrous cycle with the number of AFC on Day 7 (P = 0.42), number of corpora lutea (P = 0.44), number of recovered embryos (P = 0.18), or number of viable embryos (P = 0.11) in superovulated ewes. In conclusion, we did not find significant correlations between AFC on a random day of oestrous cycle and the superovulatory/embryos response in Santa Inês ewes.
Financial support for this study was provided by Embrapa (02.13.06.026.00.02 and 02.13.06.026.00.04) and FAPEMIG (PPM 00201-17).
