Do Your Cows Fit Your Ranch?

This is a question we are constantly asking at Mushrush Ranches. When we pay close attention, our cows give us the answer. Pregnancy checks each fall, body condition scores, and calf performance at weaning all tell part of the story. But in today’s cattle industry, that information alone is no longer enough.

With annual cow costs much higher than they were even a decade ago, every cow in the herd needs to earn her keep. We cannot afford lost revenue, extra feed costs, or additional labor tied to cows that take longer to produce their next calf. A simple pregnant versus open diagnosis no longer tells us everything we need to know.

An open cow is a cow that did not get pregnant during the breeding season. While identifying open cows is still important, even pregnant cows can vary widely in profitability.

To truly fine-tune our herd and operate as efficiently as possible, we need to look deeper than whether a cow is pregnant.

Why Reproductive Efficiency Matters More Than Ever

Among cows that do check pregnant, there can still be big differences in profitability. Those differences often come from:

• How many days pass between calves (calving interval)
• Whether a cow consistently calves early or late in the calving season

Cows that calve earlier produce heavier calves at weaning. Cows with shorter, more consistent calving intervals tend to stay productive longer and raise more calves over their lifetime. On the other hand, cows that calve late or take longer to rebreed can quietly reduce profitability, even if they remain in the herd.

Working with other seedstock producers, commercial cow-calf operations, and cattle data management specialists, we participated in developing a new way to measure this type of reproductive efficiency.

Introducing CIV (Calving Interval Value)

CIV is a phenotypic measurement that helps compare the reproductive efficiency of cows within the same herd. It is not an EPD and is not meant to be compared across different ranches or breeds. Instead, it helps answer a practical question:

Which cows in this herd consistently do the best job of calving on time and early in the season?

We first presented CIV in our March 2022 sale catalog. It highlights differences in:

• The repeatability of a cow’s average calving interval
• The timing of her calves within the calving season

Because CIV compares cows to their herdmates, it accounts for differences in management style, breeding season length, and nutrition programs.

How CIV Works

CIV looks at two components of a cow’s annual reproduction:

1. Most Probable Calving Interval (MPCI): This represents how many days typically pass between a cow’s calves, compared to the herd average.
2. Calving Season Distribution (CSD): This measures whether a cow’s calves are born earlier or later than the herd’s average calving date.

In simple terms:

CIV = MPCI + CSD

The weight given to each component is based on economics. Earlier-born calves have more time to grow and usually weigh more at weaning. Cows with longer calving intervals either raise fewer calves over their lifetime or incur more feed and maintenance costs.

Both MPCI and CSD are measured in days and centered around the herd average.

• A +30 MPCI means a cow’s calving interval is about 30 days longer than the herd average.
• A -10 MPCI means her calving interval is 10 days shorter than average.
• A +45 CSD means her calves are typically born 45 days later than average.
• A -14 CSD means her calves are born about two weeks earlier than average.

Because CIV is based on herd averages, there is no industry-wide or breed-wide “standard” value for Red Angus. The goal is comparison within the herd, not across herds.

A Note on Breeding Heifers Ahead of Cows

In herds where heifers are bred ahead of mature cows, calving intervals may not be exactly 365 days. A cow that breeds early every year may gradually move closer to a 365-day interval but may never reach it exactly.

What matters is not the absolute number of days, but how that cow performs relative to her herdmates. CIV accounts for this by comparing each cow to the herd average, allowing efficient cows to rank favorably even under different management systems.

Using CIV

CIV values are expressed in dollars ($) and represent the economic impact of a cow’s calving interval and calving timing.

In general:

• Cows with calving intervals close to or better than the herd average
• And cows whose calves are born earlier in the calving season

will have higher $CIV values.

Cows that consistently breed first-service A.I. as heifers and continue that pattern throughout their lifetime typically rank highest. Conversely, a cow may have a relatively short calving interval but still receive a lower CIV if her calves are consistently born later in the season.

How CIV Helps Guide Herd Decisions

CIV is primarily a management tool. It helps us:

• Identify the most efficient and profitable cows in the herd
• Make informed decisions about which cows to keep and which to cull (remove from the herd)
• Improve long-term herd efficiency

While CIV is mainly used to guide internal herd decisions, it also provides added transparency for bull buyers. It offers insight into the reproductive consistency and maternal efficiency of the cow families behind our bulls.

Trends in Cow Reproductive Efficiency and Calving Performance 

1. Herds using synchronized A.I. programs often have more calves clustered within the calving season than herds relying solely on natural service.
2. Shorter breeding seasons typically result in less variation in CIV values.
3. Herds that cull late-calving cows tend to maintain tighter calving windows and more consistent reproductive performance.

Thank you for reading. If you have questions, comments, or would like to receive our upcoming bull catalog and learn more about how we use CIV, please contact us at info@mushrushranches.com.