Evolution of fixed-time AI in dairy cattle in Brazil
Jose Luiz Moraes Vasconcelos1, Marcos Henrique Colombo Pereira1, Milo Charles Wiltbank2
1Department of Animal Production, FMVZ-UNESP, Botucatu, SP, 18610-000, Brazil.
Abstract:
Various programs have been used to synchronize ovulation of a fertile oocyte, accompanied by fixed-time artificial insemination (FTAI). These programs involve a series of hormonal treatments to achieve four physiologic outcomes: 1) synchronize an ovarian follicular wave; 2) optimize conditions for ovulatory follicle development; 3) synchronize corpus luteum (CL) regression; and 4) synchronize ovulation. This manuscript summarizes studies conducted in Brazil with lactating dairy cows that aimed to increase pregnancy rates to E2/P4-based programs.
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