Estratégias de manejo para aumentar a eficiência reprodutiva de bovinos leiteiros: protocolo de ciclo curto para a sincronização da ovulação e métodos auxiliares de detecção do estro

• Autor(a) principal: Silva, Thiago Vilar
• Data de Publicação: 2016
• Tipo de documento: Tese
• Idioma: por
• Título da fonte: Repositório Institucional da UFG
• Texto Completo: http://repositorio.bc.ufg.br/tede/handle/tede/5502
• topic: Manejo reprodutivo; Análise econômica; Detecção de estro; Reproductive management; Economic analysis; Estrus detection; ZOOTECNIA::PRODUCAO ANIMAL

Reproductive strategies are of great importance to reduce the operational cost of dairy farms. Thus, different management models are developed to improve reproductive efficiency by changes on nutrition, development of new protocols for synchronization of ovulation, management strategies, or others. In this context, reproductive strategies in heifers has great importance, as this category of animal represents most of the total costs of the farm. Another critical point to the dairy farm is the estrus detection capability in lactating cows. According to official surveys of the US government, the annual cost of poor estrus detection in dairy cows is more than $ 300 million. Therefore, two studies were conducted: the first aimed to evaluate the economic viability of the eight-day protocol to perform the first AI at the beginning of the reproductive management against AI performed only after estrus detection in dairy heifers. The results showed similar conception rates to those obtained after insemination performed through visual estrus detection, resulting in reduced time to pregnancy, and thus lower cost with feeding; The second study was conducted to verify the sensitivity, specificity, positive predictive value, negative predictive value and accuracy of the two mainly methods used for estrus detection in dairy cows of high production: tail painting and pedometer system. It was observed with the second study that good estrus detection rates can be obtained using both methods but the automated system performs better detection. Variables such as body condition score, number of lactation, parity and milk production if incorporated into estrus prediction model can increase the accuracy of detection of estrus by the device.