For decades, cattle frame and body size have steadily climbed across the U.S. beef industry. While feedlots have capitalized on high-growth genetics that pack on finishing pounds, cow-calf producers face a much tougher question: Does carrying larger cows actually pay off in the pasture?
During a recent episode of the South Dakota Cattlemen’s Association podcast, Cattlemen’s Call, Phillip Lancaster, Kansas State University research assistant professor of beef cattle nutrition and member of the Beef Cattle Institute, discusses modern cow size and the controversy surrounding which frame size serves an operation best.
The Finishing Floor vs. the Cow Herd: The Weaning Weight Trade-Off
Increased finishing weights are primarily an economic decision; feedlots feed cattle longer, adding more pounds due to superior feed conversion rates in modern genetics. Carcasses have not been getting docked by packers because consumer demand for beef remains strong, making it easy to tack on days to the finishing process.
Cow size has increased too, but that growth has developed over a longer period — 20 to 30 years. Lancaster explains the added frame and genetic growth potential in modern cow herds has enabled cattle to add finishing days without the large decrease in gain and feed conversion animals would have shown two decades ago.
When asked how frame score affects ranch profitability — specifically whether bigger cows raise bigger calves — Lancaster says, “That is a million-dollar question.”
Larger-framed cows generally have greater genetic potential for growth, but producers on the cow-calf side of the beef industry may not see evidence of this until weaning.
Data from an Oklahoma State University study shows an additional 100 lb. of cow weight adds only about 6 lb. of weaning weight to calves.
Lancaster notes for cow-calf producers, feed costs increase when feeding larger cows, without necessarily yielding more pounds of weaned calf per cow. Whether that trade-off is profitable depends on how producers manage their operations and available resources.
Matching Frame Size to Forage: Stocking Rates and Heifer Selection
Resources are another crucial factor to weigh when evaluating which cow size best suits an operation.
Lancaster explains forage and land resources are among the first things to consider. With larger cows, there is less grass per animal in a grazing situation, pinching available nutrients and ranch budgets.
“Where that is, is where we have struggled as an industry to say, ‘okay this is the right sized cow for these resources,’” Lancaster says.
More feed availability should mean producers can handle larger cows, but Lancaster questions, “Where is the number and how do we quantify that claim?”
Comparisons of cow sizes have been made, but there is no clear data defining which cow is more efficient beyond what biological variations are captured. Regardless of these claims, being able to manage cow herds with varying resources and environmental factors is crucial to maintaining cows’ reproductive capabilities.
For example, Lancaster suggests weaning calves earlier in drought conditions to help maintain cows’ body condition scores (BCS) for winter months. This, along with feed supply management, provides the greatest benefit to the herd.
Beyond managing resources, producers must also consider individual animal management, particularly when selecting replacement heifers.
Lancaster explains producers should be careful not to retain females solely through single-trait selection. That was how frame size increased so rapidly in previous decades, but that practice also hurt beef quality during that era.
To avoid this when selecting replacement females, Lancaster advises producers spend more time measuring and keeping track of calving dates and heifer ages, especially from a commercial standpoint. Age plays a critical role in heifers achieving puberty; if producers select the largest, most mature animals at weaning, they slowly increase mature cow size in the herd over time.
When evaluating cows, Lancaster encourages producers to assess efficiency by considering the percentage of her body weight she weans in a calf, and particularly whether the calf is above or below average weaning weight.
Precision Management: Smart Tags and the Terminal-Sire Strategy
As producers continue to seek ways to improve herd management, the industry is developing new technologies and strategies to support their efforts.
Technology is ever-changing, and the industry is starting to see greater adoption of GPS collars and smart ear tags. Lancaster says he sees the benefit of these advances specifically in animal health, helping managers detect and treat sick livestock faster. Precision tools are also enhancing individual animal management by tracking factors like feed intake, performance and supplementation.
Ultimately, aligning herd genetics with pasture capacity delivers the greatest long-term sustainability.
His best advice: “Try to moderate cow sizes and find ways to use terminal sires in your herd to add the growth potential and those calves will be a win-win for the entire beef industry.”
