Alternative low doses and routes of administering a prostaglandin F2alpha analogue to induce luteolysis in Nelore cows.
The present study was conducted in order to verify the efficacy of lower doses and alternative routes of a prostaglandin F2alpha 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, IM (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.
Meira
Cezinande
C
Department of Animal Reproduction and Veterinary Radiology, School of Veterinary Medicine and Animal Science, Sao Paulo State University, Botucatu, Sao Paulo 18618-000, Brazil. meira@fmvz.unesp.br
Pessoa
Valsair Matos
VM
Ferreira
João Carlos Pinheiro
JC
Araujo
Gustavo Henrique M
GH
Gioso
Marilu M
MM
Bicudo
Sony Dimas
SD
Oba
Eunice
E
Orlandi
Cassia
C
D026881:Acupuncture; D000818:Animals; D002417:Cattle / Q000502:physiology*; D004305:Dose-Response Relationship, Drug; D005260:Female; D007273:Injections, Intramuscular / Q000662:veterinary; D003341:Luteolysis / Q000187:drug effects*; D011374:Progesterone / Q000097:blood; D011461:Prostaglandins F, Synthetic / Q000008:administration & dosage*
D011461:Prostaglandins F, Synthetic; D011374:Progesterone; C049643:luprostenol