REVIEW: Factors Affecting Decisions on When to Calve Beef Females

The decision of when to calve beef females is critical to production efficiency and profitability in a cow and calf enterprise. Calf production and associated costs are affected by calving season because environmental conditions, stage of production, and season of the year interact to affect nutritional status and reproductive performance. Cow and calf producers typically choose to commence calving and breeding at times of the year when weather is least stressful and forage conditions are optimal. Choosing to do so can reduce the amount of supplemental feed needed to ensure acceptable pregnancy rates, resulting in reduced annual feed costs. However, the time of year when forage conditions are optimal varies across the United States because of not only environmental (ambient temperature, rainfall, day length) differences among latitudes and longitudes but also differences in soil types and topographies. Consequently, forage species and their growth characteristics differ among regions. Given such differences, feeding strategies and feed costs vary among regions. Additionally, summer heat stress, particularly in southern states, has negative consequences on reproductive performance in both the female and male and will reduce calf performance. Such a wide array of production environments, productivity levels, and associated costs will cause profitability to vary among regions of the United States, making it impossible to identify a universally acceptable date to commence calving and breeding. Consequently, the decision of when to calve beef females should be based on site-specific conditions.