Are Smaller-Framed Cattle Really More Economical?
In recent years, a common narrative has gained traction in the beef industry: smaller cows are more economical. The logic seems fairly sound - smaller animals consume less feed, so therefore they should cost less to maintain. However, when we take a closer look at data from research across multiple ruminant species (both domestic and wild) and real-world ranch operations, the picture becomes more complex - and in many cases, when looking at the bigger picture, larger cows outperform their smaller counterparts in important and measurable ways.
On our farm, calving-age heifers typically weigh between 1,400 and 1,600 pounds at around 24 months of age, while mature cows often range from 1,600 to 1,800 pounds (with a few exceptional individuals exceeding 2,000 pounds). All cows are weighed one to two weeks after calving - after losing fetal and fluid weight but before significant lactation-related weight loss - providing a consistent measure of their full weight potential so that we can calculate an accurate weaning efficiency. These cows are not bred for size; they are selected for structural soundness, maternal reliability, and the ability to thrive on pasture without grain supplementation. One standout cow weighed 2,097 lbs on her most recent post-calving weigh-in, yet continues to rebreed on her first heat, calve unassisted, and wean the heaviest calf in the herd (with excellent weaning efficiency) every year. Our biggest cow is our most efficient? That goes against what many in the industry preach - so what’s going on? Let’s take a deeper dive to see what these studies are omitting.
Frankly, the research supports what we’ve observed, but only if you look at the overall picture and not just a snapshot. A study conducted by the Louisiana State University AgCenter compared cows averaging 1,210 lbs with those weighing around 1,377 lbs. The larger cows consumed only about two pounds more dry matter per day but weaned calves an average of 32 pounds heavier (LSU AgCenter, 2020). This demonstrates that small increases in intake can yield proportionally greater returns in weaned calf weight - particularly relevant when evaluating efficiency on a per-pound basis. After all, calves are sold by weight.
Similar findings were reported in a Nebraska Sandhills study involving over 1,600 crossbred cows. Each 100 kg (220 lbs) increase in cow weight was associated with a 2.7 kg (5.94 lbs) increase in calf birth weight and a 14.8 kg (32.5 lbs) increase in weaning weight, alongside improved average daily gain (Funston et al., 2012). While smaller cows initially showed higher feed efficiency (when considering intake relative to calf weight alone), this advantage diminished once fertility and lifetime productivity were factored in. Crucially, the study noted that smaller cows exhibited reduced fertility and lower pregnancy rates, meaning fewer calves per cow over her lifetime. This fertility limitation directly offsets any feed savings smaller cows might provide and reduces total beef production relative to inputs. This is often what is left out of the conversation.
Further evidence comes from feedlot trials at Kansas State University, where larger-frame steers (51–53 inch hip height) achieved higher daily gains and heavier carcass weights with better net returns than smaller-framed animals (Kansas State University, 2018). These findings mirror the conclusions of a Canadian Journal of Animal Science review, which noted that selecting for moderate-to-large-framed cattle reduces the number of animals needed to meet beef production targets, ultimately improving economic efficiency per unit of meat produced (Canadian Journal of Animal Science, 2016). This evidence shows that larger-framed cattle can efficiently produce meat at a competitive level.
Physiological and Ecological Foundations
From a physiological standpoint, this makes sense. According to Kleiber’s Law, basal metabolic rate increases at approximately 0.75 power of body mass. This means that as animals get bigger, they use less energy per pound of body weight. Larger cows are also able to take better advantage of low-quality forage due to their greater gut capacity and longer digesta retention, as described by the Jarman–Bell Principle (Demment & Van Soest, 1985).
These concepts are supported not only in cattle but also in other ruminants. In sheep, larger-bodied ewes maintain better body condition and consistently exhibit higher conception rates, particularly in forage-based or low-input systems. An Ontario Ministry of Agriculture report found that ewes weighing over 50 kg at breeding had conception rates above 80%, compared to roughly 65% for those under 40 kg (OMAFRA, 2016). Similarly, in goats - especially those adapted to harsh or tropical environments - larger animals show better heat stress tolerance and improved utilization of low-quality forage, which translates into higher fertility and kid growth rates (Devendra, 1992).
From an evolutionary and ecogeographic standpoint, larger body size is also associated with increased cold-stress tolerance (which is quite useful in our Canadian climate). This principle - known as Bergmann’s Rule - describes how animals in colder climates tend to evolve larger body masses, which help conserve heat through a lower surface-area-to-volume ratio. This trend is observable not only in cattle but also across wild and domestic ruminants, from reindeer and bison to northern-adapted sheep and goat breeds. Fossil and paleo records reveal that as the climate cooled during the Ice Age, many large herbivores followed this evolutionary trajectory, increasing in body size over time to better cope with the harsher conditions and poorer vegetation quality (Geiger et al., 2017; McNab, 2010). Larger animals generally retain body heat more efficiently, making them better suited to withstand prolonged cold, wind, and wet conditions without compromising body condition or reproductive performance (Geiger et al., 2017; McNab, 2010).
Conversely, smaller-framed animals are more common in tropical and arid zones, where heat dissipation is more critical than heat retention. However, even in those environments, research shows that the most productive and resilient animals are often moderate-to-large in frame. These individuals tend to carry more internal reserves—body fat, muscle, and gut fill—which act as metabolic buffers during periods of stress. In real-world grazing systems, this plays out during droughts, cold snaps, excessive rainfall, or times when pasture quality drops due to delayed regrowth (Demment & Van Soest, 1985; Devendra, 1992).
Smaller cows, especially those nursing calves, tend to lose body condition more rapidly during these nutritional gaps. The combined demands of lactation and limited forage availability strain their energy reserves, increasing the risk of falling below critical body condition thresholds. This loss in condition can delay or prevent the return to estrus, reducing pregnancy rates and extending calving intervals (Funston et al., 2012; O’Connor et al., 2018). Cows bred while already in suboptimal condition—and cows that are already pregnant during periods of nutritional stress—are significantly more likely to experience early embryonic death or abortion (Missouri Extension, n.d.; Clinical Theriogenology, 2024).
Additionally, calves raised by under-conditioned cows often exhibit lower growth rates and weakened immune function, which can impact their long-term performance and survival (Morris et al., 2014). In contrast, larger cows with greater energy reserves and digestive capacity can better maintain condition through these periods, supporting timely rebreeding and healthier calf development. These differences in resilience may not be apparent in short-term studies but become increasingly significant over multiple seasons and varied environmental conditions (Devendra, 1992; McNab, 2010).
The Trouble with Weaning Efficiency
Weaning efficiency (WE) - typically defined as calf weaning weight divided by dam weight - is often touted as a convenient benchmark for maternal productivity. On paper, it seems to level the playing field by measuring how much saleable weight a cow produces relative to her size. But in practice, the metric is riddled with inconsistencies that make it difficult to interpret across seasons, let alone different herds under different management practices.
The first major inconsistency lies in how and when cow weight is recorded. Industry convention often uses weight at weaning, after the cow has raised a calf through months of lactation - frequently her lowest body condition point of the year (Funston et al., 2012; O’Connor et al., 2018). Cows under forage or heat stress may lose significant weight by weaning, which inflates the apparent weaning efficiency. In contrast, weighing cows shortly after calving - once fetal and placental weight has been shed, but before lactation takes its toll - offers a more stable and biologically representative measure of the cow’s true mass (Devendra, 1992; McNab, 2010). This method reduces the bias introduced by environmental stressors and management variability that disproportionately affect lighter cows with fewer body reserves.
This matters because smaller-framed cows are more likely to experience rapid body condition loss during periods of nutritional stress. A weaning efficiency metric that rewards cows for being lighter - even if that weight loss reflects declining health and fertility - can mask long-term inefficiencies. Larger cows, with more body reserves and greater digestive capacity, are often better able to maintain weight, rebreed on time, and support steady calf development through those same periods (Demment & Van Soest, 1985).
Another problem with WE arises from how calf weights are adjusted. The 205-day adjusted weaning weight is a standard tool - but only meaningful when applied uniformly. If some calves are creep-fed while others aren’t, or if pasture quality varies dramatically, calf weights can reflect management inputs more than maternal merit (Morris et al., 2014). Smaller cows are sometimes favored under this system simply because their calves are easier to supplement or creep feed, producing a misleading efficiency advantage.
Environmental conditions further complicate matters. In drought years, cows - especially small ones - may wean smaller calves but lose more weight themselves, paradoxically resulting in higher WE percentages. In good years, both cow and calf weights rise, but the ratio may stay flat or decline, obscuring actual gains in output. Without context, a high WE figure might mean either a highly efficient cow or a nutritionally stressed one raising a small calf on minimal reserves.
Finally, the reliability of weaning efficiency depends entirely on accuracy - and many producers don’t use scales regularly, or at all. Visual estimates or old average weights are common, and these shortcuts are especially problematic when comparing across frame sizes. A 1,350-pound cow misestimated at 1,500 skewers the entire metric and may unfairly penalize larger animals whose true contributions are greater.
In theory, the weaning efficiency metric is intended to balance calf productivity against dam maintenance cost. In practice, though - especially when applied inconsistently or without context - can produce misleading comparisons. Cows that lose weight during lactation may appear more efficient simply because they’re lighter at weaning, while cows that maintain good body condition are penalized by a heavier denominator. Larger cows, in particular, may be unfairly judged, even when their added mass reflects superior maternal capacity and long-term resilience - not excessive input cost. When these cows rebreed reliably and wean heavier, healthier calves year after year, their true efficiency becomes apparent - just not always in the weaning efficiency formula.
“Eggs in One Basket”? The Risk Argument
Another common argument in favor of smaller cows is the idea of “not putting all your eggs in one basket.” If a rancher can run more small cows for the same total feed as fewer big cows, then losing one has less impact - or so the thinking goes. While this sounds risk-savvy and forward thinking in theory, it doesn’t always play out that way in practice.
Smaller cows generally produce smaller calves and may have lower pregnancy and weaning rates. This means that even with more cows - total pounds of weaned calf per acre (or per ton of forage) may not increase - and it may even decline. If a larger cow produces heavier, healthier calves with more consistency and stays in the herd longer, the loss of one such animal could still represent a net economic gain over several smaller cows with poorer lifetime performance.
Furthermore, running more animals means higher handling and labor demands, increased infrastructure wear, more exposure to injury, and potential compounding of disease pressure. In challenging forage years or health events, more animals may not be an asset - they can be a liability. Risk mitigation isn’t only about herd size - it’s also about structural soundness, health history, and productivity per unit. A fewer number of well-built, reproductively efficient cows may offer greater consistency and long term resilience than a larger group of less-productive animals.
Practical Management and Safety Considerations
Another argument occasionally raised against larger cows is the perception that they are harder or more dangerous to manage. However, animal behavior and handling risks are more closely tied to temperament, personnel training, and facility design than to size alone. Studies in small ruminants show that flighty or aggressive temperaments pose greater risk to handlers than animal size (Kilgour & Dalton, 1984). In fact, smaller-framed cattle can sometimes give a false sense of safety, leading handlers to take fewer precautions - despite the reality that a 1,000-lb cow can cause just as much injury as a 1,800-lb cow if mishandled.
Moreover, larger cows may actually be less prone to injury during breeding, particularly in natural service systems. Although direct research comparing injury rates in cattle is limited, studies in wild ruminants such as elk and red deer support this concept: larger females tend to have higher breeding success and sustain fewer injuries during mating, whereas smaller females bred by significantly larger males are more susceptible to pelvic injuries (Clutton-Brock et al., 1982; Guinness et al., 1978). It stands to reason that cows with adequate frame and structural soundness are less likely to experience pelvic strain, hip displacement, or soft tissue trauma when bred by a mature bull. Conversely, small-framed cows bred to large bulls - which commonly occurs in crossbreeding programs pairing smaller maternal breeds with larger terminal sires - may endure increased physical stress, especially during early estrus when mounting activity is more frequent and vigorous.
Good stockmanship, calm disposition, and proper facilities ultimately have a far greater impact on safety and animal welfare than frame score alone. Well-managed large cows can be just as easy—and often more predictable—to handle as their smaller counterparts.
In The End
What’s often overlooked in the discussion around cow size and efficiency is the value of measured performance data and functional soundness. Larger-framed cows, when matched to the environment and managed appropriately, can produce heavier calves with fewer reproductive setbacks, better resilience in challenging conditions, and overall improved lifetime productivity.
Importantly, producers need to know what they’re working with to make educated management decisions - not just rely on visual estimates or breed stereotypes. If producers don’t actually weigh their cattle, assumptions about “small” and “large” are based on guesswork which has no value. What one rancher calls a “moderate cow” might actually be 1,500 pounds or more, placing her well into the mid or upper range in these studies. Without scales or proper frame scoring, it’s easy to misinterpret research findings - and overlook high-performing cows that quietly outproduce their smaller herd mates.
Efficiency should be assessed as a holistic measure—accounting for intake, reproductive success, calf output, longevity, adaptability, and management practicality—not simply minimized cow size and feed intake.
Our experience, supported by multiple peer-reviewed studies across cattle, sheep, goat, and wild ruminant production, confirms that bigger cows aren’t inherently less economical; in many cases, they are more productive, more resilient, and more profitable in the long run. You just have to take the time to read and the literature and analyze the proper numbers.
References
Canadian Journal of Animal Science. (2016). Biological Efficiency and Frame Size in Beef Cattle, 96(2), 235–246.
Demment, M. W., & Van Soest, P. J. (1985). A Nutritional Explanation for Body-Size Patterns of Ruminant and Nonruminant Herbivores. The American Naturalist, 125(5), 641–672.
Devendra, C. (1992). Goat Production in the Tropics. Commonwealth Agricultural Bureaux.
Funston, R. N., et al. (2012). Heifer Development in the Nebraska Sandhills: Dam Weight, Calf Growth, and ADG. UNL Beef Cattle Report.
Geiger, D., et al. (2017). Body size and adaptation to cold in ruminants. Journal of Animal Ecology, 86(3), 585–595.
Kansas State University. (2018). Frame Score Effects on Feedlot Performance and Profitability.
Kilgour, R. J., & Dalton, D. C. (1984). The behavior of goats in relation to handler safety. Applied Animal Behaviour Science, 12(2), 123–134.
LSU AgCenter. (2020). Effect of Cow Size on Calf Weaning Weight and Feed Intake.
McNab, B. K. (2010). The Physiological Ecology of Vertebrates: A View from Energetics. Cornell University Press.
Missouri Extension. (n.d.). Nutritional Stress and Reproductive Loss. Retrieved from extension.missouri.edu
Morris, C. A., Hickson, R. E., & Hickey, S. M. (2014). Influence of maternal body condition on calf growth and survival. Livestock Science, 161, 101–109.
O’Connor, T. P., et al. (2018). Nutritional stress and reproductive performance in beef cattle: A review. Journal of Animal Science, 96(3), 789–804.
Ontario Ministry of Agriculture, Food and Rural Affairs (OMAFRA). (2016). Reproductive Performance in Sheep Flocks.
Clinical Theriogenology. (2024). Review on Nutritional Causes of Embryonic Loss and Abortion in Cattle.