Cow-Calf Commentary for Iowa Cattleman Magazine

By Randie Culbertson, Cow-Calf Extension Specialist

May 2026

Are you ready for breeding season?

Breeding season will soon be upon us, and the question you need to ask is "Are you ready?" And more importantly, is your cow herd ready? As you start to plan for this summer’s breeding season, think about how to set your herd up for success.

A pre-breeding checklist

Work through these questions before turnout to breeding pastures. Asking at pregnancy check is too late!

  • Have all bulls had a BSE this spring?
  • Are bulls and cows vaccinated and healthy?
  • Are cows and heifers in a BCS of 5 to 6?
  • What do your pastures look like? Are the available forages adequate to support the herd?
  • What is your mineral and vitamin supplementation plan?
  • Is your bull-to-cow ratio appropriate for pastures size and terrain?

What shape are your bulls in?

Bull fertility problems can quickly and quietly tank an entire breeding season, and you may not know until pregnancy check in the fall. (See last month’s article Spring Training for Your Bulls).

Every bull going out this summer should have a complete breeding soundness exam (BSE) to evaluate the bull’s breeding ability. Don’t assume that last year’s results still hold. A BSE should be conducted every year prior to bull turnout. A bull that ran a fever from something such as foot rot would need roughly 60 days post-fever to return to normal sperm production. You don’t want to have a bull with suboptimal sperm production out with cows during a 60-day breeding season. You should regularly check your bulls throughout the breeding season to make sure they are healthy and getting the job done. Not checking them could result in an increase of open cows if an issue arose.

Keep in mind your bull-to-cow ratio. For mature bulls, the standard ratio is one bull per 25 to 30 cows. For bulls under two years of age, the recommendations are one female per month of bull age (i.e. - 18-month-old bull could service 18 females). The ratio may change depending on pasture size and topography. If using estrus synchronization, research has shown that these ratios still hold true when using mature bulls.

What do your cows look like?

Nutrition plays a crucial role in reproduction, and making sure your cows are at an adequate body condition is critical. It is difficult to add body condition once lactation demands kicks in. Cows that calve in poor body condition are at risk of losing weight while nursing, resulting in a slow resumption of normal estrous cycles and ultimately rebreed. Cows and heifers should be at a body condition score (BCS) of 5 to 6 going into the breeding season. For animals at a lower BCS going into the breeding season, the odds are increased that they will fail to breed early or at all.
Ensuring that cows and bulls have adequate feed resources during the breeding season is important for reproductive success. Get your forages tested and know what you are dealing with before turnout. Also, have a plan for mineral and vitamin supplementation while cattle are out on pasture.

Considering estrus synchronization?

For producers looking to tighten their calving window with an added bonus of increasing weaning weights, estrus synchronization combined with AI is worth serious consideration, but it requires planning well ahead of the breeding season. A well-executed synchronization program can shorten the breeding season to 45 days while maintaining pregnancy rates comparable to longer natural-service seasons. Keep in mind that a low estrus response at AI usually points to fewer cows cycling, which may be an indication of nutrition not being met weeks prior, not the protocol itself. Synchronization protocols, semen, and supplies need to be ordered and confirmed weeks in advance, and anyone involved in handling and inseminating cattle should be trained and ready. The Beef Reproductive Task Force maintains up-to-date protocol options suited to different herd sizes and management situations. To assist with planning, the Estrus Synch Planner can help you plan ahead by providing a schedule with times for implementing each step of the protocol, in addition to providing a list of all the supplies needed. If you have never synchronized before, talk to your veterinarian or an ISU Extension beef specialist for more information.

 

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