Calving distribution provides insight into herd profitability

Most cow-calf producers have a calving book in their pockets at calving time.

A few may have made the technological leap to a smartphone application or a computer-based recording system, but the tried and true pocket calving book is still common.

This record keeping system may not be high tech, but it can tell you more than which calf belongs to which cow.

One of the simplest ways to track the reproductive success of a cow-calf herd is to graph a calving distribution. This is simply a graphical representation of how many calves are born in each 21 day period of the calving season.

Most computer based cow-calf record systems can generate a calving distribution, but you can also create a simple calving distribution by recording calf births on a calendar or in your calving book.

Calving distribution is important because it is the only easily accessible reproductive event in a cow-calf herd.

In most herds, we don’t know the exact breeding dates for each cow unless we are using artificial insemination. The only reproductive event that is easy to track is the cow’s calving date.

However, we know that the other reproductive events, such as when a cow comes into heat and when it is bred, are highly related to the date on which it calves.

To create a calving distribution, count the cows that have calved during the first 21 days of the calving season.


Divide this number by the total number of cows that calve in the calving season and multiply by 100 to get the percentage of cows calving in the first 21 days.

Repeat this process for each of the next two 21 day periods to calculate the percentage of cows that are calving in each 21 day period of the calving season.

The goal is to have at least 65 percent of the herd calving in the first 21 day period of the season. These cows were probably cycling at the start of the breeding season and were bred in the first 21 days of the previous breeding season.

They are also more likely to be cycling at the start of the next breeding season and will be more likely to become pregnant in the following year, provided that they are in good body condition and on a good plane of nutrition.

Tracking the median calving date is another way to measure the success of the calving distribution. The goal is to have half of the cow herd calve by day 18 of the calving season.

Reproduction is one of the most important economic indicators of success in a cow-calf operation. A live calf on the ground in the spring is the first step toward having a product to sell at the end of the year.

There are lots of reasons for trying to achieve the goal of 65 percent of the cow herd calving in the first 21 days of the calving period.

Cows that calve in the first 21 days will wean heavier calves at the end of the year.


Each extra 21 day period before weaning can result in at least an extra 50 pounds of weaning weight for the calves born in this time period.

Heifer calves born in the first 21 days that are retained as replacement heifers are heavier and more likely to be cycling as a yearling heifer.

Having a large proportion of calves born in the first 21 day period also creates a more even and uniform calf crop, which simplifies management procedures and results in a marketing advantage.

Lots of producers with mediocre calving distributions are still getting by with reasonable pregnancy rates, but they could significantly improve their economic returns by focusing on improving their calving distribution.

Less than ideal calving distributions are often a reflection of poor reproductive management or poor nutritional management, especially over the winter feeding period and into the early breeding season.

An ideal calving distribution will result in fewer open cows and heavier calves at weaning time. It’s easy to calculate and interpret.

What does your herd look like?