My View From The Country

There Is No Magical Cow Size That Guarantees Profitability

Table of Contents:

Efficiency is a relatively simple thing that just happens to be complicated.

I had several people this week dispute my statement from last week that biological efficiency doesn’t vary among the accepted range in mature size in the industry (“The Bearish Math On The Beef Industry Doesn’t Add Up”). The bottom line is that maintenance costs rise as mature size increases, but it’s not a 1:1 relationship. In fact, the general rule of thumb is that maintenance costs are calculated by taking mature size to the .7 power.

The same is true with production gains, which also aren’t 1:1. The data indicates that, from a biological efficiency standpoint, input vs output, there is no inherent advantage of one size cow over another.

Animal scientists will tell you maintenance costs are affected by the relationship between surface area and mass. An elephant, for example, has less maintenance requirements per pound than a mouse or hummingbird. While that’s true, the advantage that larger cows would have in this regard is negligible enough not to be significant in the range that we typically see cows in production.

The inverse of that is that an animal still needs to be matched to its environment. Theoretically, in a low-quality forage environment, the limiting factor to meeting requirements is intake capability. If a cow has maintenance requirements too large relative to what it can consume, then it will begin to shut down reproduction or some other biological process. So, while biological efficiency may not be the factor, there is potentially more risk of decreased profits associated with cows that aren’t appropriately matched to their environment.


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Others rightly have pointed out that there are moderate cows with as much growth as larger cows. In fact, this is a testament to what the industry has and is continuing to do from a genetic standpoint. We’ve been quite successful in bending the growth curve, having more rapid early growth while not increasing mature size. And I know many seedstock operators who actually are seeing mature size decrease as growth increases in their herds.

We’re doing a great job of defying the genetic relationship that exists between growth and mature size. As a result, some of the general rules of thumb are no longer as valid as they once were.

It’s generally true that maintenance costs increase with mature size. But we’ve also found that within similar metabolic weights and stages of the growth curve, there are large, significant and moderate to highly heritable differences in feed efficiency. Not all cows are created equal when it comes to efficiency.

Some of the old Standardized Performance Analysis (SPA) data tells the story – low-cost producers had more moderate cows and yet also had more growth. Looking at that data, it can be argued that part of this difference was that low-cost producers tended to have better feed environments, which allowed them to more consistently express the level of growth they had selected for in their herd. I’d also point out that such producers also tended to pay more for their genetics and were thus more successful in selecting those animals that defied the genetic relationships between growth and mature size.

Efficiency has always been a difficult trait to measure because so many variables come into play when measuring it. For instance, milk is a relatively expensive way to put gain on a calf, and it’s not very efficient. Yet, no one wants a cow that only provides companionship.

Efficiency of gain of milk production declines as you move further down an animal’s growth curve. For example, gains from milk production have more advantage to a producer who sells at weaning, than to one who retains ownership of calves through the feedyard.

Discuss this Blog Entry 12

Dennis Hoyle (not verified)
on Mar 14, 2014

I agree that nothing gaurantees a profit. The data I have seen says that in general small cows have an advantage. Eric Moussel from South Dakota State has some very good research on this subject and there are several studies that indicate that same thing. The beautiful thing about our industry is that I can do it the way I want to and if I am right I get to reap the rewards, and I am reaping the rewards. Just small or large is not the only thing that counts but there is a difference in general. More pounds of calf weaned per acre is an advantage.

John R. Dykers, Jr (not verified)
on Mar 14, 2014

And Dennis Hoyle is quite correct up to weaning. We carried our beef through to the customer and the kitchen. Portion size matters and is different for different customers. Tenderness is the most consistent customer requirement. Young beef is more tender than old.
Great article, Troy Marshall. The variability of environment and markets is the fun and the challenge for each of us to find a profit in what we do and how we do it.

Avatar (not verified)
on Mar 14, 2014

1) There is no inherent advantage in biological efficiency for a wide range of cow weights (the only relevant measure of size).
2) Cows of vastly different size are equally efficient on low-quality forage as long as quantity of forage is adequate, and milk production is equivalent to body size.
3) It is cows of higher milking potential that are penalized on low-quality forage, rather than cows of larger size.
4) We often confuse effects of cow size and milk. They should be considered separately.
5) A factor often overlooked in the cow-calf segment is that lighter calves bring more per pound than heavier. This can definitely affect economics.
5) Because there is so much variation in the production conditions under which beef cows are raised, there is much more variation in what is the optimum, compared to swine, dairy, and poultry. And this will always be so.

Dave Nichols (not verified)
on Mar 17, 2014

You are SPOT on regarding 4). The genetic ability to produce milk effects metabolic efficiency when a cow in not lactating. And it effects metabolic efficiency of their steer calves for their whole life time.

The beef industry has largely ignored this fact and does not understand targeting optimum physiological end points. Dr. C.J. Brown () after weighing every animal in the University of Arkansas Angus herd every 28 days said "the most efficient cow weighs the same as her steer when he grades USDA Choice. I haven't seen any data or have experienced anything in my 60+ years of breeding and raising cattle that would dispute Dr. Browns conclusions

Charlie Kraus (not verified)
on Mar 15, 2014


I was stuck where you are for a long time. A heard of smaller cows simply could not be as thermodynamically efficient as a herd of large cows. That is simple physics.

It finally took working through Chip Hines' "Slantwise Guide To Prosperity" to see the value of smaller cattle in my cow/calf operation. The key lies in putting a realistic dollar value on the value of cattle sold and more importantly on the daily cost of feeding cows and calves based on body weight. Smaller cattle turn dollars into dollars more efficiently than bigger cattle, even if bigger cows turn pounds of forage into pounds of beef more efficiently.

I don't know how or if that translates in a seedstock operation. Economic work by Stan Bevers in Texas, David Lauman in Oklahoma, and others has not found that more size, growth, and milk translate into more profits under actual ranching conditions.

W.E. (not verified)
on Mar 17, 2014

The magic cow size for us is an efficient cow that can wean a good proportion of her weight on grass with no additional feed, rebreed on time, and offer no problems. In our environment, it's much harder for a cow that weighs 1500 lbs. to do that than a cow that weighs 1000 or 1100.

avatar (not verified)
on Mar 22, 2014

Where do you find sires these days to produce 1000 lb cows?

Charlie Kraus (not verified)
on Mar 25, 2014

Dare I say it? I think I shall. It is Pharo Cattle Company.

Todd1013 (not verified)
on Mar 25, 2014

In our experience on our farm the big cows sure do eat a lot more than the small cows. We had some of those 1800# cows that could eat you out of house and home. Whether the cow is 1100# or 1800# she had better bring home and wean a calf that is at least half her weight or more to make any kind of profit. Our 1200# cows can do that very easy but the 1800# cow that can wean a 900# calf in the same amount of time are far and few between. Most of our smaller cows can equal or out due weaning weights of the larger cows so when it comes to cost of feed per cow vs #s of weaned calf the smaller cows due make you more money, as long as the quality of the small cows is good.

Anonymous (not verified)
on Mar 26, 2014

Regardless of weather or not your pastures can support large or small cows would someone not favor a more moderate cow that will allow for more cows on a fixed number of acres?

Take for example 160 acres that will support 1 AU per acre. That's 114 calves produced from 1,400 lb cows or 123 calves from 1,300 lb cows. That's nine extra calves on the same ground.

Anonymous (not verified)
on Mar 28, 2014

" The data indicates that, from a biological efficiency standpoint, input vs output, there is no inherent advantage of one size cow over another."
Mr. Marshall --this is why you are wrong. Let's forget about regurgitating hearsay from some animal scientist that has no real life experience and has adopted some fuzzy math.

The Facts
1. Reducing the annual cost of production is the key to a more profitable operation -- period! --end of story

Since the largest inputs to any cow calf program is Hay -sadly:

1. Input costs for hay/feed are greatly decreased on moderate cows.
2. We can produce more calves on the same amount of acreage by maintaining a herd of moderate framed cattle.
3. The moderate cow has the advantage of having a higher relative intake because she has a larger metabolic weight. This means a smaller cow can have a higher relative intake in pounds of dry matter consumed per 100 pounds of body weight, than a larger cow. This is why a smaller cow commonly has a better body condition under same environment than a larger cow. This increases BCS,health and reproductive rates.
4. She will also have the advantage of earlier maturity, earlier marbling and generally better body condition because once she meets her maintenance needs, the excess feed consumed is used for production such as daily gain and marbling, for reproduction or for work such as grazing.
5. Calves from more moderate framed cows and moderate framed bulls will also have earlier maturity, earlier marbling and generally a better BCS throughout their life.

Selecting for tall, lanky and slab-sided bulls and cows have a lot to do with the problem the average rancher is having in making a profit when the going gets tough. These cattle require a lot more energy for maintenance and in tough times just don't get enough nutrition to perform or reproduce.

Under difficult conditions the cow with the highest relative intake, will have the advantage. Matching the environment to the type of cattle we raise is a very important aspect in the cattle business, but this, normally, goes without saying -- for most experienced cattlemen/women.

So, while biological efficiency may not be the factor, there is potentially more risk of decreased profits associated with cows that aren’t appropriately matched to their environment.

on Mar 29, 2014

In terms of profitability, I would include in the comparisson the weight of the calf at the weaning. If the coefficient between the calf weight at the weaning by the weight of cow is higher than 0.50 we are talking about efficient cows in terms of calf production.

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What's My View From The Country?

As a fulltime rancher, opinion contribur Troy Marshall brings a unique perspective on how consumer and political trends affect livestock production.


Troy Marshall

Troy Marshall is a multi-generational rancher who grew up in Wheatland, WY, and obtained an Equine Science/Animal Science degree from Colorado State University where he competed on both the livestock...

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