Alternative low doses and routes of administering a prostaglandin F2 alpha analogue to induce luteolysis in Nelore cows

• Autor(a) principal: Meira, Cezinande de [UNESP]
• Data de Publicação: 2006
• Outros Autores: Pessoa, Valsair Matos, Ferreira, João Carlos Pinheiro [UNESP], Araujo, Gustavo Henrique M., Gioso, Marilu M., Bicudo, Sony Dimas [UNESP], Oba, Eunice [UNESP], Orlandi, Cassia
• Tipo de documento: Artigo
• Idioma: eng
• Título da fonte: Repositório Institucional da UNESP
• Texto Completo: http://dx.doi.org/10.4142/jvs.2006.7.4.387; http://hdl.handle.net/11449/14492
• topic: bai-hui acupoint; cows; luprostiol; luteolysis; progesterone; prostaglandin

The present study was conducted in order to verify the efficacy of lower doses and alternative routes of a prostaglandin F2 alpha analogue, luprostiol (PGF), for the induction of luteolysis and the precipitation of estrus in nonlactating Nelore cows (Bos taurus indicus). A conventional dose (15 mg) of PGF was compared to doses lower than the conventional dose, which ranges from 10 to 50%, that were administered intramuscularly (IM), intravulvosubmucosally (IVSM), or in the Bai-hui acupuncture site located within the lumbosacral area. The cows were administered PGF 8 day after estrus in the presence of a corpus luteum, and randomly assigned to the following groups: G1 (positive control), 15 mg, IM (n = 23); G2, 7.5 mg, IM (n = 23); G3, 3.75 mg, I M (n = 24); G4, 7.5 mg, IVSM (n = 25); G5, 3.75 mg, Bai-hui acupoint (n = 24); and G6, 1.5 mg, Bai-hui acupoint (n = 25). The results indicated that 50% of a conventional dose of PGF (7.5 mg) resulted in a complete luteal regression (plasma progesterone < 1 ng/ml) at Hour 48, and hastened estrus, regardless of whether or not PGF was administered IM or IVSM. Comparatively, 10 or 25% of the conventional dose, even when administered to the Bai-hui acupoint, resulted in an initial reduction in the concentration of progesterone at Hour 24, followed by an increase observed at Hour 48. In conclusion, 25% of a conventional PGF dose administered via the Bai-hui acupoint proved inadequate to induce a complete luteal regression, whereas 50% of a conventional dose administered IM or IVSM was found to be the minimal dose required to induce effectively a complete luteal regression, and to precipitate the onset of estrus in nonlactating Nelore cows.