Collapse bottom bar
Subscribe
Herd

How to Properly Cull the Herd — Part II

by Dr. James C. Kroll   |  March 28th, 2017 0

Over the years, our institute’s research has offered insight into the critical question of when a buck should be culled — that is, if he should be culled at all.
In analyzing our data based on age as a predictor of ultimate antler quality, we see that until a buck is 3 1/2 years old, there’s no reliability in predicting his antler size at maturity (4 1/2 or 5 1/2 years). This really gives you only one year to remove a buck in any culling scheme. However, removal at maturity has some positive benefits, as the majority of offspring are produced by bucks of these ages.

Cull-the-Herd

Is the smaller buck on the right a cull? It’s impossible to be sure, because he hasn’t yet reached the age of 3 1/2. Photo by John R. Ford

So no buck should be removed from the herd as a “cull” until he’s at least 3 1/2. And how many bucks in the average whitetail herd are at least that old? The answer tends to be: not many! In some areas, especially with heavy public hunting pressure, the percentage is minuscule. So unless you have a somewhat natural buck age structure, culling is a moot point.

Now let’s consider herds in which there is reasonable buck age structure. Can we in these cases achieve anything by culling bucks? And if so, which criteria should be used? A buck’s third set of antlers is a reasonable predictor for what he will be in the next two years, when as a breeder he’ll have his greatest impact on herd genetics.

You might have read about studies that appear to contradict what I just wrote. However, I’ve carefully analyzed them, and they clearly substantiate that, while bucks of all ages breed, those in the 4 1/2 to 5 1/2 “breeding pool” produce more offspring individually.

There’s also the question of what we’re trying to achieve. If we analyze Boone & Crockett scores, we see the total lengths of the tines is a huge component. Hence, a buck with only eight mainframe points is at a disadvantage in scoring well. As there’s heritability in the number of antler points a buck grows, culling 3 1/2-year-olds with eight or fewer points has merit.

Another trait with some degree of predictability is antler conformation. There are only five possible rack shapes: circular, oval, square, rectangular and diamond. To me, the most beautiful and impressive conformation is the square. It has what I call the “wow” factor. So in the rare instance when culling is appropriate, I try to remove bucks that have eight or fewer points and don’t have square racks.

Non-Typical Puzzles
With non-typicals, the waters get even cloudier. A non-typical can be produced by genetics and/or environment. Many of these racks result from antler damage during growth. They also can occur because of damage to a hind leg (or, less often, a front leg).

The most common non-typicals are double- or triple-beam bucks. Usually this abnormality occurs on just one side. As the antlers begin growth, the cells around the pedicel are very similar to stem cells in embryos. Each cell contains the genetic code to produce a certain set of antler type. Yet as the antlers develop, the cells in the antler and tine tips lose their stem cell nature and genetic complexity. Significant trauma to the growing tip of the antler bud very early on can cause the cells in tissue fragments to attempt to grow a complete antler, thus producing the extra beam(s). If you examine one of these racks, usually you’ll find counterparts to the brow tines and other antler features on each extra beam.

Interestingly, the buck’s next set of antlers might not exhibit such modification. In general, it takes a buck two or three antler sets to restore the original configuration. So if you remove him because he has “freaky” antlers, you might well be culling a deer that doesn’t even have inferior genetics.

Likewise, a buck that receives significant trauma to a back leg might produce a non-typical antler on the opposite side of his body (due to the way nerves connect to the brain). He’ll probably repeat the malformation the rest of his life — but again, the deformity has nothing to do with genetics, so why cull him?

Is Culling Legitimate Management?
The very short answer to this question is, “No.” The more complete answer is, “Only in cases in which you have complete or nearly complete control over the herd.” While culling can work, only in specific situations is it practical.

The normal bell curve for a deer population comes into play here. The left and right ends of the curve represent the best and worst animals, respectively, so these occur in low numbers. If a fellow hunting an 80-acre parcel shoots a 3 1/2-year-old 8-pointer with a small frame, he’s helping the herd within the broader landscape. On the other hand, if he shoots the most genetically superior buck in the area, he’s doing the opposite. I know of a 100,000-acre Texas ranch (not high-fenced) that “shot out” its top-end trophy potential within only a few years by taking just 12 of the best bucks from the herd annually. The best harvest scheme for the most overall good is a random harvest of bucks that have reached maturity.

When imposed properly, antler restrictions are actually the best way to “cull” the herd. Furthermore, states holding their rifle seasons after the rut also are “culling” their herds properly. Removal of an active breeder after the rut has relatively little effect on herd genetics.

The real cull to consider is removal of the right number of does — especially old ones — to control population growth. Younger doe groups are made up of daughters of the best bucks, provided you’re giving them a chance to reach maturity. A 9 1/2-year-old doe was produced by the herd genetics you had a decade ago. So as a manager, I strive for herds with a low average age of does and a high average age of bucks.

In Conclusion
Culling wild whitetails is a fascinating but confusing topic. The reality of it is, there’s generally little need to cull a herd unless you’re also protecting younger bucks and have control over total harvest. That reduces culling to a few situations, more often than not on private land surrounding by other managed land. In the end, trying to manipulate antler genetics is the least important factor in growing trophy bucks.

Cull-the-Herd
related

How to Properly Cull the Herd — Part I

It happened one fall day back in the 1980s, just as we were starting to make progress in getting folks to manage deer on...

Load Comments ( )
back to top