Pre-TAI protocol strategies to increase reproductive efficiency in beef and dairy cows

• Autor(a) principal: Sales, José Nélio de Sousa
• Data de Publicação: 2019
• Outros Autores: Simões, Luiz Manoel Souza, Orlandi, Raphael Evangelista, Lima, Eduardo Alves, Santos, Ana Paula Castro, Bottino, Miguel Pizzolante, Silva, Luiz Augusto Capellari Leite da, Souza, José Camisão de, Dias, Marcelo Maronna, Massoneto, João Paulo Martinelli, Scandiuzzi Junior, Luiz Antônio, Freitas, Bruno Gonzalez, Guerreiro, Bruna Martins, Bastos, Michele Ricieri
• Tipo de documento: Artigo
• Idioma: eng
• Título da fonte: Repositório Institucional da UFLA
• Texto Completo: http://repositorio.ufla.br/jspui/handle/1/40600
• topic: Conception rate; Timed artificial insemination; Progesterone; Vacas leiteiras - Reprodução; Taxa de concepção; Inseminação artificial; Hormônio luteinizante; Progesterona

Ovulation synchronization protocols are well established in beef and dairy cows. However, the protocol response rate is around 70-90%. In beef cows, factors such as inadequate nutrition and calf presence negatively impact the response of progesterone (P4)/estradiol-based ovulation synchronization protocols by interfering with GnRH release and consequently reducing LH pulsatility and final follicular development. In dairy cows, protocols based on GnRH and prostaglandin (Ovsynch) are the most widely used in the world. However, the efficiency of Ovsynch is dependent on the presence of a large follicle at the time of administration of the first GnRH. In these ovulation synchronization protocols, pre-synchronization protocols (Prostaglandins, Double Ovsynch and P4synch) are usually attempted in an effort to increase responses. Thus, the objective of this review was to discuss pre-ovulation synchronization strategies (administration of injectable P4 or energetic/protein supplementation or pre-synchronization with intra-vaginal progesterone devices) aiming to increase the LH pulsatility in beef cows or induce the formation of a GnRH-responsive follicle at the beginning of the Ovsynch protocol in dairy cows.