Efficiency of superovulatory response to P-24 protocol in fixed time embryo transfer in Brahman cattle

Eficiencia de la respuesta superovulatoria del ganado Brahman al protocolo P-24

Objective. To evaluate the efficiency of superovulatory response to P-24 protocol in fixed time embryo transfer in Brahman cattle. Materials and methods. Twelve Brahman cows donors with more than 60 days postpartum were used. Twenty one cows received a superovulatory treatment based in Protocol P-24. Embryos were collected through the conventional method, and the embryos were classified (IETS). Results. An average of 9.1 embryos were collected, 4.4 were considered for direct transfer, 3.7 were considered for freezing and 3.2 were classified as degenerated. According to the stage embryos were classified as: morulae (32.6%), early blastocyst (38%) and blastocyst (18.5%). Effect was presented (p<0.05) in the number of successive superovulations on the production of frozen embryos; however, there was no effect (p>0.05) on the other variables studied. Effect was presented (p<0.05) in the average production of structures recovered, and transferable and frozen embryos among the donors with an output greater than or equal to 5, and less than 5 transferable embryos. By contrast, there was no effect (p>0.05) on the average production of degenerate embryos and unfertilised oocytes among both groups. Nevertheless, the proportion of these ones is greater in the donors with a lower production of transferable embryos (50 and 22.4%) vs. donor with the highest production (39.3 and 14%) for degenerated embryos and unfertilised oocytes respectively. Conclusions. The Brahman cattle has an efficient superovulatory response to P-24 protocol for fixed time embryo transfer.

1. Bo GA, Moreno D, Cutaia L, Baruselli SP, Reis EL. Manipulação hormonal do ciclo estral em donadoras e receptoras de embriao bovino. Acta Sci Vet 2004; 32(suppl):1-22.
3. Bo GA, Baruselli PS, Chesta PM, Martins CM. The timing of ovulation and insemination schedules in superstimulated cattle. Theriogenology 2006; 65(1):89-101 https://doi.org/10.1016/j.theriogenology.2005.10.008
5. Baruselli PS, Marques MO, Reis EL, Nasser LF, Silva RC, Menegatti JA et al. Adequação da dose de FSH (Foltropin-V) em protocolos de superovulação de vacas Nelore (Bos taurus indicus) com inseminação artificial em tempo fixo (SOTF). In: XVII Reuniao anual da sociedade brasileira de tecnología de embrioes; 2003, Fortaleza, Brasil. Acta Sci Vet; 2003b. (31):244-45.
7. Parker R. Using body conditions scoring in dairy herd management. Fact Sheet (Ontario), January 1989.
9. Zanenga CA, Marques MO, Santos IC, Valentin R, Baruselli PS. Comparacao entre dois protocolos de superovulacao com inseminacao artificial em tempo fixo em vacas Nelore (Bos indicus). In: XVII Reuniao anual da sociedade brasileira de tecnología de embrioes; 2003, Fortaleza, Brasil. Acta Sci Vet; 2003.
11. Palma GA. Biotecnología de la reproducción. 2ª. Ed. Mar del Plata: Reprobiotec; 2008.
13. Stringfellow D, Seidel S. Manual of the international embryo transfer society. 3rd edition. IL, USA: Savoy; 1998.
15. Martins CM, Marques MO, Silva RC, Baruselli PS. Adequação do protocolo de superovulação com inseminação artificial em tempo fixo em Bos taurus. [Tesis de Maestría]. Sao Paulo: Universidade de Sao Paulo; 2005.
17. Bo GA, Baruselli PS, Chesta P. Dinámica folicular, momento de la ovulación e inseminación artificial a tiempo fijo en donantes de embriones. En: Jornadas de actualización en biotecnologías de la reproducción en bovinos (IRAC); Córdoba, Argentina; 2006.
19. Hasler JF. Comparation between conventional in vivo and in vitro production of embryos in bovine embryo transfer programs. En: Congreso de Reproducciòn Animal, Rosario, Argentina; 2000.
21. Donalson L. Dose of FSH-p as a source of variation in embryo production from superovulated cows. Theriogenology 1984; 22:205-212. https://doi.org/10.1016/0093-691X(84)90433-3
23. Ireland JJ, Ward F, Jimenez F, Ireland JLH, Smith GW, Lonergan P et al. Follicle numbers are highly repeatable within individual animals but are inversely correlated with FSH concentrations and the proportion of good – quality embryos after ovarian stimulation in cattle. Human Reproduction 2007; 22: 1687-95. https://doi.org/10.1093/humrep/dem071