Research Shared On Cow Size Relative To Carcass Weight

Dr. Paul Beck’s core message is straightforward: bigger cows are not inherently better for ranchers

NOTE: this article was originally published to Livestock Weekly on Wednesday, April 22, 2026. It was written by  Colleen Schreiber.

VIA WEBINAR — Increasing cow size has essentially no benefits to the cow-calf producer. Also, cow size has little impact on carcass size.

That was essentially the message offered by Dr. Paul Beck, Oklahoma State University Extension beef cattle nutrition specialist during a recent Rancher Thursday webinar which focused on cow size and post weaning management effects on carcass size. He also offered some thoughts on how rising carcass weights impacts ranch sustainability.

As a way of introducing the topic of discussion, Beck offered some points to ponder. He noted that the segmented structure of the beef industry by nature leads to a lot of independent decision making across each sector. That in turn creates biological and economic inefficiency, said Beck.

He also stressed that a post weaning backgrounding phase preceding finishing sets the foundation for subsequent feedlot performance and carcass development. Also, management and nutritional strategies during backgrounding exerts lasting effects on growth efficiency, finishing performance and carcass merit.

He pointed to some of the key backgrounding factors that affect finishing performance including rate of gain and the type of backgrounding system, drylot versus a pasture-based system, as well as bodyweight and body composition prior to going into the finishing phase at a feedlot.

Turning then to the topic of discussion Beck first pointed out that carcass weights have increased about eight pounds per year since the mid-1960s. The biggest increases began in the mid-1990s through 2005 due to a tremendous increase in cow bodyweight.

“We went from a 6.5-pound increase per year in cow bodyweight up to about an 18-pound increase,” said Beck.

He attributed the jump to the use of continental breeds and growth related EPDs, which improved selection efficiency.

Since about 2005, the cow growth rate has moderated some back down to about 3.9 pounds per year though he noted a lot of variability.

“In the last few years, it appears that cow weights are once again tracking much higher.”

Beck said there are concerns within the cow-calf industry on cow size and its impacts on range condition and susceptibility to drought. He noted that a 1300-pound cow requires 20 percent more dry matter intake than a 1000-pound cow, which corresponds to a 20 percent increase in maintenance energy requirements.

He shared highlights of a long-term stocking rate study conducted at the Southern Plains Range Research Station in Woodward, Oklahoma, during the 1950s and 60s that supports the reason for concern. Researchers looked at three different stocking rates on cows that averaged 1045 pounds. Stocking rates were 22, 16 and 11 cows per acre.

What they found was that as stocking rates increased, weaning weights decreased. Weaning weight per acre did increase in six of the eight years with increased stocking rates.

Both were classic responses, Beck said. Specifically, both increased up to a point then costs of increasing the stocking rate outweighed the increased weaning weight per acre. At that point net returns began to decrease.

“Researchers identified that the break point for this was at about 0.07 animal unit equivalent per acre or 14.5 acres per cow,” said Beck.

Put another way the optimal stocking rate at the Woodward station with cows weighing 1045 pounds was 14.5 acres per cow.

Beck looked at the numbers again recently. He first noted that the average cow bodyweight at the Woodward station had increased by about seven pounds per year. Thus, while the economically optimal stocking rate was still 0.07 AUE per acre, because the cows were bigger the optimal stocking rate should now be 18.2 acres per cow.

He also found that while cow bodyweight per year increased by about seven pounds, calf weaning weights only increased 2.4 pounds per year.

“Increased stocking rate influences the amount of weaning weight produced per cow,” Beck reiterated.

He took another snapshot look from 2003 through 2015. During 2010 through 2013, drought years, weaning weights were down. However, the point he wanted to impress upon participants was that when stocking rates aren’t adjusted because of larger cows an operation is less resilient or more susceptible to climate upsets like drought and that, in turn, increases production risks.

“Cow efficiency, a measure of weaning weight per pound of cow bodyweight, was up around 50 percent in the years previous to the drought,” said Beck. “It fell to below 40 percent during the drought years.”

He next looked at increases in fed cattle hot carcass weight using USDA data. He noted that hot carcass weights for both steers and heifers have “pretty consistently” increased by about 4.8 pounds per year. He also noted that the steers haven’t increased quite as much as the heifers.

“That indicates that heifer production is starting to catch up with steers due to these growth promoting technologies directed towards heifers,” said Beck.

From this data, he pointed specifically to 2024 and 2025, which showed an above trend line, an increase of some 20-plus pounds of hot carcass weight, an increase which has caused a lot of concern. However, Beck opined that the increase isn’t much different from other increases in previous time points and it potentially has more to do with drought feeding and other economics in the cattle feeding industry, namely high prices, cheap corn, reduced discounts for heavies and the incentive to keep the hotel full.

When looking at the transfer of cow bodyweight to offspring hot carcass weight, expressed as pounds of hot carcass weight per 100 pounds of cow bodyweight, based again on USDA data, that ratio has only increased about nine percent over the last 66 years, a 0.12 percent per year increase.

“Increases in efficiency in the feeding sector has not really helped us capture that much more hot carcass weight per pound of cow bodyweight,” said Beck.

Recently the trend from 2020-25 increased by about 0.27 percent annually. While the industry has made “massive strides” in beef production efficiency using growth implants, beta agonists, improved feeding management and the like, Beck reiterated his theory that the increases in carcass weight have very little to do with increasing cow size, and much more to do with other economic drivers, namely external market factors.

He looked at this deeper then, drawing on data from a variety of sources to put together 5000 records for both spring and fall calving herds in Texas, Oklahoma, Arkansas and Louisiana. That data included cow bodyweight, finishing weights, both steers and heifers, both calf feds and yearlings, as well as carcass data. He also noted that most incorporated a pasture-based backgrounding system.

The cows averaged 1200 pounds and the finishing liveweight of the offspring averaged 1390 pounds. The average hot carcass weight was 888 pounds with a convertible cow bodyweight efficiency to hot carcass weight of the offspring of about 74 percent.

Looking at fall versus spring calving herds in these production systems, there were decreases in harvest liveweight, hot carcass weight and the efficiency measure. Also, calf fed heifers versus steers were lighter at harvest and their score efficiency was lower.

Beck told participants that feeding yearlings versus calf feds more than makes up for the impacts of either calving season or heifers in these systems.

“There is a lot of power in these backgrounding programs that allow us to feed yearlings better instead of calves,” said Beck.

To that point he compared finishing a yearling steer from a 1200-pound cow versus a calf fed steer out of a 1500-pound cow and showed that there was essentially no difference in hot carcass weight, said Beck.

He summed up this data set by reiterating several key takeaways. First, there was decreased productivity in the fall versus spring calving herd, which backs the need to match the production system to the environment. It’s why the warm season grass-based system works best for cow herds in the south.

Another takeaway is that the increased rate of physiological maturity decreased performance and efficiency of heifers. However, the increased rate of change in heifer hot carcass weight versus steers showed that modern technologies are reducing these differences, said Beck.

Additionally, he reiterated that feeding yearlings completely offset cow size, season and sex effects.

He also stressed again that the 300-pound increase in cow bodyweight comes with lots of costs, namely increased dry matter intake, increased maintenance energy, increased reliance on stored forages and added production risks.

Bottom line, across the whole beef industry, higher profits from the feedlot sector do not offset the reduced profitability of the larger cows at the ranch of origin.

Wrapping up Beck offered some pointed conclusions:

“Each sector of the segmented beef industry has little or no interest on their impact on previous or subsequent stages of production, unless retaining ownership,” Beck opined.

He also told participants that the least efficient way to increase hot carcass weight in the beef industry is by increasing cow bodyweight.

“Increasing cow bodyweight has really no benefit to the cow-calf operator,” said Beck.

Finally, his take home message was that productivity of the entire beef industry is optimized by matching cow size and calving season to the environment of the ranch and by increasing productivity of heifers to match steers.

“Across segments of the beef industry, optimizing pre-finishing management offers opportunity to enhance carcass output and overall system profitability more so than simply increasing mature cow size,” Beck concluded.