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| Ambrose,Divakar Justus; Colazo,Marcos Germán; Kastelic,John Patrick. |
| Fertility of dairy cattle is generally decreasing. Overall estrus detection efficiency in lactating dairy cattle is low, as expression of estrus is often compromised. Consequently, undetected estrus, low AI-submission rates, and long inter-breeding intervals are the main contributors to poor reproductive efficiency. Although failure to become pregnant is the most common reason for culling dairy cattle, pregnancy rates could be improved by increasing the AI-submission rate through increased estrus detection efficiency, timed insemination (Timed-AI), or timed embryo transfer (Timed-ET). In these protocols, ovarian follicular development and luteolysis are controlled, culminating in synchronous ovulation in most cows. There are several modifications to... |
| Tipo: Info:eu-repo/semantics/article |
Palavras-chave: Cystic ovaries; Gonadotropin releasing hormone; Porcine luteinizing hormone; Progesterone; Synchronization of ovulation; Ultrasonography. |
| Ano: 2010 |
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S1516-35982010001300042 |
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| Demeterco,Danilo; Henry,Darren Dwayne; Mercadante,Vitor Rodrigues Gomes; Lamb,Graham Cliff; Gaievski,Francisco Romano; Weiss,Bruno; Turbay,Gustavo Nascimento; Segui,Márcio Saporski; Weiss,Romildo Romualdo; Betiol,Melina Andreia Formighieri; Kozicki,Luiz Ernandes. |
| The effect of an intramuscular versus intravenous administration of gonadotropin releasing hormone (GnRH) at fixed-time AI (FTAI) on the pregnancy rates of crossbred Bos indicus beef cows was evaluated. Pluriparous nursing calv cows (n=120) were synchronized as follows: d 0 cows received a 2.0 mg injection of estradiol benzoate (EB) and insertion of a controlled intravaginal progesterone releasing device containing 0.558 g of progesterone, d 8 removal of the progesterone device , a 0.15 mg injection of prostaglandin F2α (PGF), a 1.0 mg injection of EB, and 400 IU injection of equine chorionic gonadotropin. Fifty-four hr after PGF, all cows were exposed to FTAI and a 0.084 mg injection of GnRH was administered either via Vena caudalis (n=60), or via... |
| Tipo: Info:eu-repo/semantics/article |
Palavras-chave: Gonadotropin releasing hormone; Fixed-time artificial insemination; Intravenous intramuscular administration. |
| Ano: 2014 |
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S1516-89132014000300008 |
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