A long-term experiment challenges genetic culling—but leaves important management questions
Harvesting bucks with small antlers is a familiar strategy among deer managers. The idea is straightforward: remove bucks with below-average antlers, allow better-antlered males to do more breeding, and improve antler size in future generations.
But antler development is influenced by more than genetics. Age, nutrition, environmental conditions, and early-life development all affect the rack a buck produces. And removing smaller-antlered males does not guarantee that the remaining bucks will pass along genes for larger antlers.
A 2026 study published in Wildlife Monographs examined selective harvest at two South Texas ranches over approximately 20 years. The researchers tested different harvest intensities, monitored antler development across age classes, tracked reproductive success using DNA, and estimated the heritability of antler traits.
Their findings challenge the idea that culling smaller-antlered bucks is a reliable way to produce lasting genetic improvements. They also raise important questions about how managers distinguish genetic potential from the effects of nutrition, age, and development.
The Big Takeaway
Even intensive, age-specific culling did not produce convincing evidence of lasting genetic improvement in antler size under the conditions tested.
At King Ranch, selective harvest did not increase average antler size by age class relative to an untreated control area.
At Comanche Ranch, intensive culling produced larger average antler measurements in some older age classes during the harvest period. However, those results did not develop into a consistent, lasting improvement after harvesting stopped.
The researchers also found that early antler size was associated with mature antler size, but the relationship was not strong enough to reliably identify which young bucks would eventually become top-antlered deer. DNA-based analyses showed that the heritability of antler size was relatively low and uncertain in young bucks and substantially higher in mature bucks.
These findings do not mean antler genetics are unimportant. They show why selecting animals based on visible antler characteristics does not automatically produce the expected genetic response.
Two Experiments Tested Selective Harvest
King Ranch: Selective harvest in a free-ranging population
From 1999 through 2004, researchers selectively harvested bucks in a treatment area of approximately 3,815 hectares (9,425 acres) at King Ranch. A nearby area served as a control. Deer could move freely between the study areas and surrounding properties.
The harvest criteria targeted yearling bucks with fewer than six antler points and older bucks with eight or fewer points. Researchers captured deer annually to estimate age, measure antlers, and monitor the population.
The average annual harvest rate was approximately 8.6% of antlered males.
After six years, selective harvest had not increased antler size by age class relative to the control.
The researchers identified several possible limitations, including the harvest rate, movement of yearling bucks into and out of the study area, and environmental variation affecting recruitment.
The results suggested that removing smaller-antlered bucks at that intensity was not sufficient to change the antler-size distribution of the population in the expected direction.
Comanche Ranch: More intensive harvest under restricted deer movement
Researchers conducted a follow-up experiment at Comanche Ranch from 2006 through 2012, then continued monitoring through 2018.
The study included three areas: an approximately 72.8-square-kilometer moderate-harvest area, a 14.2-square-kilometer intensive-harvest area, and a 20.2-square-kilometer control area.
The intensive-harvest and control areas were completely enclosed by high fencing. The moderate-harvest area was approximately 85% enclosed by high fencing, with the remainder bordered by a major highway and a less restrictive fence.
The moderate treatment targeted older bucks, whereas the intensive treatment applied age-specific antler criteria across multiple age classes. The average annual harvest rates were approximately 19% in the moderate treatment and 48.3% in the intensive treatment.
During the harvest period, the intensive treatment had larger average antler measurements than the control among bucks aged 3.5–4.5 years and those aged 5.5 years or older. In the moderate treatment, the difference was observed among the oldest bucks.
However, the researchers did not find a consistent, lasting improvement across age classes after culling stopped. By the end of the study in 2018, the overall results did not support the predicted enduring genetic response.
This is an important result because the Comanche Ranch experiment restricted deer movement and applied considerably more intensive harvest pressure than the King Ranch experiment. The lack of lasting improvement could not be dismissed simply as a consequence of deer freely moving between treatment areas.
A Buck’s First Rack Provides Some Clues About His Future
The researchers also examined whether antler size at a young age predicted antler size at maturity.
They compared gross Boone and Crockett scores at different ages with scores at 5.5 years or older. The correlations were:
| Age when antlers were measured | Correlation with mature antler score |
|---|---|
| 1.5 years | 0.35 |
| 2.5 years | 0.51 |
| 3.5 years | 0.60 |
| 4.5 years | 0.62 |
The relationship became stronger as the bucks aged.
On average, a yearling with smaller antlers was more likely to have smaller antlers as a mature buck than a yearling with larger antlers. But the correlation at 1.5 years was modest, so first-year antler size was a relatively weak predictor of an individual’s eventual mature score.
The researchers did not identify an antler-score threshold or a particular age at which a buck could reliably be ruled out as a future top-antlered deer.
More importantly, predicting mature antler size is not the same as identifying genetic potential. A young buck can develop smaller antlers because of his inherited traits, environmental conditions, early-life nutrition, or a combination of influences.
What Did the DNA Analysis Reveal?
The Comanche Ranch researchers collected tissue samples and used DNA-based paternity assignments to construct pedigrees and estimate the heritability of antler traits.
For gross Boone and Crockett score, the estimated heritability values were:
| Age class | Estimated heritability |
|---|---|
| 1.5 years | 0.136 |
| 2.5 years | 0.160 |
| 3.5–4.5 years | 0.308 |
| 5.5 years or older | 0.682 |
These values describe the proportion of variation in antler score within the study population associated with additive genetic differences under the conditions studied. They do not mean that a particular percentage of an individual buck’s antlers is genetic.
The estimates for young bucks were especially uncertain, with credible intervals extending to zero. In contrast, the estimate for bucks aged 5.5 years or older was substantially higher.
The researchers also found that permanent environmental effects contributed to variation in antler traits among older bucks. In other words, factors beyond additive genetics could help explain why an individual repeatedly produced larger or smaller antlers.
The results do not prove that antler size at a young age is unrelated to genetics. Rather, they show that early antler development is a less reliable basis for genetic selection than mature antler development.
What about maternal effects?
The researchers built genetic pedigrees around DNA-based paternity assignments, but they could not include mothers in the heritability analysis. Consequently, they could not independently estimate maternal contributions or determine how much of the relationship between early and mature antler size reflected maternal influences.
That matters because a doe’s condition during pregnancy and nursing can affect her fawn’s development. A young buck that begins life at a nutritional disadvantage may produce smaller antlers, even if his genetic potential is not inherently poor.
The study did not determine how much maternal nutrition contributed to the results. It therefore cannot be used to conclude that a small first rack reliably identifies a buck with inferior antler genetics.
Could Nutrition Have Influenced the Results?
Yes. The researchers recognized that environmental conditions could influence antler development and the effectiveness of selective harvest.
Rainfall in South Texas varies substantially among years, affecting natural forage availability and quality. A buck may grow different-sized antlers in different years depending on the conditions he experiences.
At Comanche Ranch, the researchers provided supplemental feed across all three study areas. Feeders were spaced approximately every 70 hectares (173 acres), and the feed contained about 20% crude protein and 3.0 kcal/g of digestible energy. It was available from February through November each year, with tube feeders holding approximately 900 kilograms of feed.
This was a substantial feeding program. It would be incorrect to characterize the experiment as though the deer received no nutritional support.
But access to supplemental feed does not demonstrate that every deer consumed the same quantity, met every nutritional requirement, or experienced identical natural-forage conditions. The antler study did not directly measure each buck’s complete nutritional history or quantify annual natural forage quality and quantity for every animal.
A concurrent study at Comanche Ranch found that supplemental nutrition altered the relationship between deer density and population dynamics under the conditions tested. This further complicates attempts to generalize the results to properties where natural forage is more limiting.
The key point is that nutrition was an important part of the study’s setting, but it was not possible to separate every nutritional and developmental influence from genetic effects.
Could Culling Smaller-Antlered Bucks Free Up Resources for Better Bucks?
This is a separate management question—and a reasonable one.
If deer numbers exceed the habitat’s ability to provide sufficient nutrition, removing some animals can reduce competition for available forage. Remaining deer may then have access to more food, potentially improving body condition, growth, and antler development.
That benefit would not necessarily depend on changing the herd’s genetics. It could occur because surviving bucks receive better nutrition.
However, the benefit depends on whether food is actually limiting, how much competition the harvested animals were creating, and whether the remaining deer can access the resources that become available.
The Comanche Ranch experiment did not directly test whether culling smaller-antlered bucks improved antler growth by reducing competition for natural forage. All study areas received supplemental feed, and researchers did not establish that removing smaller-antlered bucks improved the nutritional intake of higher-scoring bucks.
This distinction matters for real-world management.
A property with excessive deer density and limited forage might benefit from population reduction. But if the specific objective is improving mature buck growth, the relevant question is whether deer density and nutrition are limiting performance—not whether the deer selected for removal have small antlers.
Culling may improve the conditions for surviving deer without producing any genetic improvement. The 2026 study did not establish whether that mechanism occurred.
Can Managers Reliably Cull Bucks Within Specific Age Classes?
The Comanche Ranch researchers used age-specific harvest criteria, but real-world managers face a practical challenge: determining the age of a living buck.
In the study, researchers captured bucks annually, estimated age using tooth replacement and wear, measured antlers, collected tissue samples, and marked deer for future identification. Their methods were far more intensive than the typical trail-camera-based management program.
On an ordinary property, managers generally estimate a buck’s age using body characteristics such as leg length, body depth, neck development, and overall musculature. These indicators can often distinguish a yearling from a mature buck, but they become less reliable when distinguishing bucks in adjacent adult age classes.
Trail cameras can help managers track individual bucks over several seasons. A buck first photographed as a fawn can be assigned a much more reliable age class later if the identification is maintained. But a single photograph of an unfamiliar mature buck rarely establishes his exact age.
This matters when deciding which animals to cull. A manager can apply age-specific harvest guidelines, but mistakes in age estimation are inevitable. Antler size should not be used as the primary shortcut for estimating age when it is also the characteristic used to select bucks for removal.
Even if a manager correctly estimates age, a small rack does not reveal whether that buck has inferior breeding value.
What Does This Mean for Deer Managers?
The study does not establish that selective harvest is always inappropriate. Managers may have legitimate reasons to remove particular age classes or reduce the male population.
But the evidence suggests caution when the goal is to improve antler genetics.
Three findings are especially important:
Young antlers provide limited information about mature antler size. Yearlings with smaller antlers tend to have smaller mature racks on average, but the relationship is far from definitive for an individual buck.
Antler size does not reveal genetic breeding value by itself. The study found low and uncertain heritability estimates for young bucks. Nutrition, environmental conditions, maternal influences, and other developmental factors complicate the interpretation of a first rack.
Reducing competition and changing genetics are different objectives. Removing deer can improve nutritional conditions when density is limiting resources, but that does not necessarily create a lasting genetic change. The Comanche Ranch experiment did not establish that culling smaller-antlered bucks improved antler growth by freeing up resources for the remaining deer.
For managers pursuing larger mature bucks, it is important to distinguish among the goals of reducing deer density, improving nutrition, changing age structure, and selecting for heritable traits. Those objectives can overlap, but success in one does not guarantee success in the others.
Where the Findings Have Limits
The research is unusually valuable because it combined long-term field experiments with DNA-based pedigree analyses and multiple harvest intensities. It also tested selective harvest in free-ranging deer and in more controlled, fenced populations.
Nevertheless, the experiments took place in South Texas, where environmental conditions differ from those in many other deer regions. The Comanche Ranch deer also received supplemental feed, and the study did not fully isolate annual natural-forage conditions or maternal influences on development.
The treatments did not span enough generations to demonstrate every possible long-term genetic response. The findings should not be interpreted as proof that selective harvest could never change antler genetics under any circumstances.
Instead, they show that even intensive, age-specific culling did not produce convincing evidence of lasting genetic improvement under the conditions tested.
The Bottom Line
A buck’s first rack can provide some information about the antlers he is likely to grow as a mature deer. But it cannot reliably establish whether he carries genes for inferior antler development.
Across approximately 20 years of experiments, researchers found no consistent, lasting genetic improvement from the selective-harvest strategies tested. Mature antler size was substantially heritable, but the genetic signal was less clear in young bucks, whose antlers were also influenced by environmental and developmental factors.
Culling may still have a role in population management, and reducing deer density may improve nutrition where forage is limiting. Those are different objectives from genetic improvement, however, and the study did not demonstrate that harvesting small-antlered young bucks delivers all three benefits.
Culling smaller-antlered bucks may change the deer a manager sees today. Producing genetically larger-antlered deer in future generations is a much more demanding task.
Source study: Draeger, D. A., et al. (2026). Effects of selective harvest on antler size of white-tailed deer in Texas, USA. Wildlife Monographs, 222(1), e70013. Read the full study.
Related research: DeYoung et al. (2019). Linking White-Tailed Deer Density, Nutrition, and Vegetation in a Stochastic Environment. Read the related study.
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