Publicação: Effects of temporary calf removal and eCG on pregnancy rates to timed-insemination in progesterone-treated postpartum Nellore cows
Carregando...
Data
Orientador
Coorientador
Pós-graduação
Curso de graduação
Título da Revista
ISSN da Revista
Título de Volume
Editor
Elsevier B.V.
Tipo
Artigo
Direito de acesso
Acesso restrito
Resumo
The objective was to evaluate the effects of temporary calf removal (TCR), eCG administration, or both, in a progesterone-based protocol. Suckled Nellore cows (40-80 d postpartum, n = 443) with body condition scores from 2.0 to 3.5 (5-point scale) on three farms were all given a synchronizing protocol (PEPE). At the start (designated Day 0), cows were given an intravaginal device (1.0 g of progesterone) and 2.5 mg of estradiol benzoate (EB) im. on Day 8, the device was removed and cows were given PGF(2 alpha) (150 mu g of D-cloprostenol im), followed in 24 h by 1.0 mg EB im, and 30-36 h thereafter, fixed-time AI. The design was a 2 x 2 factorial; main effects were TCR (54-60 h; from device removal to FTAI) and eCG treatment (300 IU im, concurrent with PGF(2 alpha)). Transrectal ultrasonography was done on Days - 10 and 0 to detect anestrus (absence of a CL at both examinations) and similar to 30 d after FTAI (pregnancy diagnosis). Data were analyzed by logistic regression. The following variables did not significantly affect pregnancy rates: farm, postpartum interval, cyclicity, inseminators, and semen (sire). Overall, 77% of the cows were deemed anestrus. Pregnancy rates were similar (P > 0.05) among treatment groups: Control (54/108 = 50.0%), TCR (44/106 = 41.5%), eCG (63/116 = 54.3%), and TCR + eCG (49/113 = 43.4%). Pregnancy rate was higher in multiparous than primiparous cows (186/360, 51.7% vs. 24/83,28.9%, P < 0.01), but was not significantly affected by cyclicity status or body condition score. In conclusion, temporary calf removal, eCG, or both, did not significantly increase pregnancy rate to timed-insemination in a progesterone-based synchronization protocol in postpartum Nellore cows with acceptable body condition. (C) 2009 Elsevier B.V. All rights reserved.
Descrição
Palavras-chave
Fixed-time artificial insemination, Progesterone, Bovine, eCG, Temporary calf removal
Idioma
Inglês
Como citar
Theriogenology. New York: Elsevier B.V., v. 71, n. 3, p. 519-524, 2009.
