Choosing the optimum time to calve beef cows involves thinking through a multitude of factors such as potential for extreme weather, availability of grazed forage, marketing and seasonality of calf prices, and availability of labor. Thirty years ago, the logic used for choosing a calving season focused on maximizing calf nutrient intake. At about 3 to 4 months of age, the calf’s nutrient requirements exceed the cow’s milk production, and thus calf nutrient intake and growth could be increased by coinciding this time with the time of highly nutritious forage. In order to accomplish, cows needed to calve in February and March for most latitudes. However, this results in increased feed costs because lactating cows consume more harvested forages and the nutritive value of harvested forages is generally not adequate to meet the nutrient requirements of early lactation cows. Thus, supplemental feed is usually necessary to keep cows in adequate body condition (≥ 5) prior to breeding to ensure high pregnancy rates.

Matching the calving season with the onset of green pasture synchronizes the high nutrient demands of the cow during early lactation and breeding with the time of maximum forage nutritive value. By doing this, stockpiled forages and crop residues can meet the nutritional requirements of cows through December reducing winter hay feeding. Additionally, cows that calve in synchrony with forage nutritive value do not require supplemental feed to maintain body condition prior to breeding. Figure 1 shows the difference in winter hay and supplemental feed usage and delivered feed costs for cows in a Kansas native range forage system with an average calving date of March 1 or April 15.

Many factors affect the sale price of calves including supply and demand, cost of gain the feedlot, and geopolitical issues, all of which the producer has very little control over. Several analyses of performance and financial records indicate that the most profitable operations are those that have low cost of production, which the produce has more control over. Even though later born calves will be lighter at the same sale date and likely even at the same age, controlling costs can improve net returns. Thus, matching cow requirements with forage nutritive value by adjusting the calving season can increase the economic sustainability of a beef operation.

Figure 1. Estimated winter hay and supplement usage, and delivered feed costs for beef cows with an average calving date of March 1 or April 15. Feed costs are calculated using $60/ton and $200/ton for hay and supplement, respectively.