Lundy erika
Extension and Outreach Beef Specialist / Iowa State University

As many cow herds are gearing up for breeding season, you may find yourself in a situation where you’re still waiting for late-bred females to calve. These late calvers can be time-consuming, create management problems and, if left unmanaged, are even profit-eaters. Here are some considerations to help you determine what to do with those late-bred females.

The first step is to evaluate the situation. This includes determining when females are expected to calve, assessing feed resources and studying the current markets. Answers to these questions should help you determine what route you should take. Regardless of your plan to manage late-calving cows, for best results, these females need to be managed separate from the rest of the herd.

For some females, there may be an opportunity to move them up a few weeks in the calving season, although this can be an uphill battle. The postpartum anestrus period where reproductive organs recover from calving and prepare to initiate cyclicity again is approximately 45 to 50 days post-calving for the majority of cows. The length of this period depends on nutrition status at calving and during initial lactation, age and calving difficulty. Utilizing progesterone, commonly in the form of a controlled internal drug release (CIDR) used in a synchronization protocol, can be effective to try to jump-start estrus. A CIDR should be utilized no sooner than 21 days post-calving with best results when used after 45 days.

Although a female may not fit in your desired calving window, she may fit into someone else’s. It may be more feasible to part ways sooner and sell as bred females, or it may pencil to sell as pairs with young calves at side. If resources are adequate and you can create a uniform group of calves, there may be value in early weaning and selling females early in the fall. However, this approach requires diligence to follow through on your decision so you don’t find yourself in the same situation next spring.

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There are several benefits to a defined calving season including similar nutritional requirements for cows based on similar stages of production, better scheduled labor, more effective health management and improved cow herd fertility. A defined calving season starts with a defined breeding season. Be diligent, maintain records, and stick to the plan.