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By Billy Cook

Most of you will have weaned your spring calves by the time you read this article. So, how did they do? The common answer is, "Well, they weaned at so many pounds." This is like asking a college football addict to describe his team's last game with one statistic — there are many other factors to tally other than calf weaning weight.

This article will address the factors to consider in order to effectively evaluate your cowherd's performance, and will give you some national averages with which to compare your herd. The national averages come from 1997 National Animal Health Monitoring System (NAHMS) studies.

A cow has to perform a few basic tasks to help keep a cattleman in business. These include: become pregnant, give birth to live calves, provide adequate nutrition and care to her calf, rebreed in a timely manner, and raise the calf until it is weaned. I will examine the relevant data that you should consider collecting in a natural progression throughout the production system (birth through weaning).

Five-and-one-half percent of all calves die before weaning. Of this 5.5 percent, 2.1 percent are born dead, 1.1 percent die within 24 hours of birth, an additional 1.1 percent die within 24 hours of age to 3 weeks of age, and 1.2 percent die within three weeks of age to weaning. The take-home message here seems simple — pay particularly close attention to your cows and newborn calves at calving and for the first three weeks of life.

Another thing to keep tabs on is the number of cows or heifers requiring assistance at birth. The NAHMS study reports that 97.3 percent of cows required no assistance at birth, and only 0.9 percent required a hard pull. A hard pull is defined as any mechanical intervention required to assist calving. When considering heifers, 83.3 percent of heifers required no assistance calving with 5.1 percent requiring a hard pull. The remaining percentage required only minimal assistance. The take-home message is not earth-shattering news — focus more time and attention on your heifers at calving.

The national average weaning weight (WW) is approximately 550 lbs. for steers and 525 lbs. for heifers. An age-adjusted WW will allow for more meaningful comparisons between cows and calves. The formula for adjusted 205-day WW is:

Adj. 205 day WW = (WW-birth weight)/wean ing age in days X 205 + birth weight + age of dam adj. factor

Once you calculate the adjusted WW, ratio the data to get a feel for which cows are producing calves with unacceptable WW.

Weaning is the most common time to palpate cows for pregnancy. The national average for pregnancy percentage is 92 percent. However, the NAHMS data reports that only 35 percent of producers have their cows palpated. This is a shocking statistic, since determining which cows are open allows producers to effectively cull open cows or at least to manage the two groups separately until open cows can be marketed or exposed to the bull for breeding.

The old standby calculation of most probable producing ability (MPPA) is defined by the Beef Improvement Federation as an estimate of a cow's future superiority or inferiority for a repeatable trait (such as progeny weaning weight) based upon the cow's past production in comparison to her contemporaries, her number of past records, and the repeatability of the trait in question. MPPA is simply an indication of the within-herd rank of the cow's ability to wean calves with high weaning ratios, taking into account the number of calves produced. As you can see, MPPA can be a very effective tool for culling those cows that don't produce at an acceptable level, and can be figured like this:

N = No. of calves included in the cow's average;

C = Average weaning weight ratio for all calves the cow has produced;

0.4 = Repeatability for weaning weight ratio 

Remember that MPPA is used most effectively within your own production system with cows that are managed similarly.

In addition to individual cow performance, consider measures of cowherd performance such as pounds of calf weaned/cow exposed (the national average is 475 lbs.), calving percentage (90%), weaning percentage (87%), and replacement rate (20%).

Now, I realize this sounds like a lot of information to keep track of and calculate, but in reality, very little record keeping is needed. It all can be kept in the IRM red book and compiled once a year.

So this year when someone asks you how your calves did, you may want to have the whole game summary, not just information from a single offensive series.


When evaluating your herd's performance, there are many factors to consider in addition to weaning weight.

© 1997-2014 by The Samuel Roberts Noble Foundation, Inc.