In vivo embryo production in cows superovulated 1 or 2 days after ovum pick-up
Ricardo S. Surjus A , Alexandre B. Prata A , Marta Borsato A , Fernanda C. S. Z. Mattos B , Mariana C. Martins da Silveira B , Gerson B. Mourão A , Alexandre V. Pires A , Milo C. Wiltbank C and Roberto Sartori A D
+ Author Affiliations
- Author Affiliations
A Department of Animal Science, College of Agriculture ‘Luiz de Queiroz’ (ESALQ), University of São Paulo, Av. Pádua Dias, 11, CP 9, Piracicaba, SP 13418-900, Brazil.
B College of Veterinary and Animal Science, São Paulo State University, Distrito Rubião Júnior, Botucatu, SP 18618-970, Brazil.
C Department of Dairy Science, University of Wisconsin, 1675 Observatory Drive, Madison, WI 53706, USA.
D Corresponding author. Email: robertosartori@usp.br
Reproduction, Fertility and Development 26(4) 527-532 https://doi.org/10.1071/RD12398
Submitted: 13 December 2012 Accepted: 15 March 2013 Published: 9 May 2013
Abstract
The present study evaluated superovulatory responses and in vivo embryo production in cows treated with FSH starting 1 or 2 days after ovum pick-up (OPU). Thirty-three non-lactating Nelore cows were subjected to aspiration of all follicles ≥3 mm for OPU. After OPU, cows were randomly divided into two groups in which the follicle superstimulatory treatments with FSH started 1 or 2 days after OPU (Groups D1 and D2, respectively). Data are presented as the least squares mean ± s.e.m. The number of follicles ≥3 mm before OPU was similar between groups (~34); however, cows in Group D2 had more follicles ≥3 mm on the first day of FSH (15.2 ± 2.3 vs 7.6 ± 1.7; P = 0.04) and a higher ratio of the number of follicles at first FSH/number of follicles before OPU (0.41 ± 0.04 vs 0.24 ± 0.02; P = 0.01). In addition, Group D2 cows had a greater superovulatory response than did cows in Group D1 (18.9 ± 2.8 vs 9.1 ± 1.9 corpora lutea, respectively; P < 0.03). However, there was no difference in the total number of recovered ova and embryos from cows in Groups D2 and D1 (5.1 ± 1.4 vs 4.9 ± 1.3, respectively; P > 0.10). Nevertheless Group D2 cows had more freezable embryos than Group D1 cows (3.2 ± 1.1 vs 1.3 ± 0.5, respectively; P < 0.05). Cows from Group D2 had a much higher proportion (P < 0.001) of follicles ≥8 mm compared with follicles ≥6 mm and <8 mm at the time of the last treatment with FSH. In conclusion, to obtain a greater production of viable embryos in superovulated cows after OPU, it is recommended to wait at least 2 days before starting FSH treatment.
Additional keywords: cattle, follicle aspiration, FSH.
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