Factors That Influence Fertility in Natural and Synchronized Breeding Programs

Reproductive failure is a major source of economic loss in the beef industry. The majority of this loss occurs because cows do not become pregnant during a defined breeding season. Therefore, the goal of any breeding program is to maximize the number of females that become pregnant. This means that fertility plays a major role in the success of any breeding program. This review will focus on the factors that affect pregnancy rates over specific days of the breeding season in both natural service and synchronized breeding programs. Since pregnancy rates are a product of both estrous detection rates and conception rates, comparisons will be made between synchronized and non-synchronized cows bred by natural service or by artificial insemination.