http://www.qdma.com/forums/showthread.php?t=4708Citer :
Thayer.qdma04-07-2006, 10:38 PM
Bryan tends to a website in his home region call tndeer.com. A recent post asked about high grading of deer and Bryan whipped out this post:
The most important concept to understand is the difference between an individual bucks genetic potential and his actual antler expression--in essence, how much antler material he actually grows. First, no buck in the wild ever expresses all of his genetic potential. Dealing with the stresses of life in the wild draws away too much of his bodily resources to allow those resources to go fully towards antler production. Exactly how much of his potential he expresses is largely determined by the local conditions--food resource volume and quality throughout the year especially during winter, how severe the winters are, the herd dynamics of the area, etc.
Second, most bucks do not express their maximum antler size until around 6 1/2. Again, the difference between maximum expression at 6 1/2 and genetic potential is determined by local conditions. In the Midwest, the difference between the two will be much less than in TN, as the Midwest has such superior food resources in both volume and quality (nearly unlimited quantities of agriculture grown on the most fertile soils in North America). Exactly how much the difference actually is is unknown. That experiment hasn't been done yet. But if someone forced me to guess, I would have to say that in TN, the average fully mature buck at peak antler development, in the wild, probably grosses around 130, while if those animals had been raised in captivity with all stresses of life removed and fed unlimited volumes of high-quality food they might produce on average 50 more inches of antler growth.
But back to the discussion at hand, first, no buck in the wild ever expresses all of his genetic potential. Second, a buck has to reach full maturity to express his maximum antler development. Young bucks express very little of their genetic potential because so much of the resources they consume are used for body growth instead of antler development. However, when all young bucks are being born at about the same time, hence have equal growing time in their early years, antler expression as a yearling may be an indicator of their genetic potential. In essence, large-antler yearlings tend to be larger antlered mature deer and small antlered yearlings tend to be smaller antlered mature deer, but only when they all have equal growing time and equal access to food resources as fawns and yearlings. However, these differences in expressed antler development and their link to future expression show up strongest only in controlled experiments, where each young buck is given equal food resources. In the wild, this rarely occurs because bucks have different quality mothers. Some mothers are more dominant than others, hence have access to more/better food resources and will produce more milk for their fawns leading to healthier button bucks and yearling bucks. So far, the only "in the wild"
study that are showing this link between yearling antler development and later development are in areas with phenomenally tuned-up deer herds, such as the King Ranch, where 50+% of the buck population is 5 1/2 or older. Considering nowhere in TN has a buck age structure that good, I question whether anywhere in TN would see the same link except in the most extreme cases of genetic potential (very high or very low).
Commonly in the Southeast, where buck age structures are below optimal and sex ratios favor females, the rut is not as tightly timed as it could be, resulting in fawning dates that are not as tightly timed as they could be. When fawning times are not tightly timed, the later-born bucks are generally "behind the curve" in both body growth and antler development. These late born bucks generally do not catch up in antler development until at least 3 1/2 and often 4 1/2. And they generally never catch up in body growth. Lost body growth opportunities as a young buck are apparently lost forever.
Now that we have all that established, what about high-grading? If hunters are using an Antler Point Restrictions, say 4-points-on-a-side, they might end up killing any yearling bucks that produce 7+ point antlers as yearlings. In the Southeast, in the wild, most 7+ point yearlings were born earliest and had good mothers (usually dominant mothers). However, the smaller yearling bucks--many of which were late-born and/or had poorer mothers (less dominant)--are protected from harvest due to their lower antler development as yearlings. Yet their lower antler development as yearlings probably has nothing to do with their genetic potential. They may have excellent genetic potential, but their late birth and/or poorer food intake as young bucks kept them from expressing much of that potential as a young buck. In this Antler Point Restriction, the smaller antlered yearlings survive to advance in age at a much higher rate than the large antlered yearlings (many of the large antlered yearlings are harvested).
The larger antlered yearlings that are killed off as yearlings may not have had any more genetic potential than the protected smaller-antlered yearlings, they just were born earlier and/or had better, more dominant mothers. So removing these bucks may have no effect what-so-ever on the antler production of bucks that live to maturity in the area (only those that had smaller antlers as yearlings). In essence, there has been no "genetic" high-grading, hence no long-term reduction in antler growth at maturity. However, those large-antlered, early born yearlings often do produce the largest racks at 2 1/2 and 3 1/2 (the effects of early-birth versus late-birth in antler development lasts at least through 3 1/2). So removing the largest-antlered yearling bucks certainly does remove the bucks that will be your largest antlered 2 1/2 and 3 1/2 year-old bucks. But by 4 1/2, those differences should disappear.
So if high-grading the largest antlered young bucks causes no permanent "genetic" problems, and the only result is a temporary reduction in antler development at 2 1/2 and 3 1/2 year-old bucks, what's the problem? The problem is not biological but simply a problem from hunters' perspectives. Most hunters implement QDM practices because they are tired of only killing spike, fork-horn and basket 6-point yearlings, scoring at best 40-60 gross. Through QDM, they aren't attempting to produce "monster" or "trophy" bucks, they simply want to kill bucks with antlers bigger than 40-60 gross. In most QDM programs, hunters are thrilled to kill 2 1/2 year-olds averaging in the 90s gross and 3 1/2 year-olds averaging in the 110s gross. But if the best yearlings are being removed each year, the average 2 1/2 and 3 1/2 year-old buck antler development may fall to 75-85 gross and 95-105 gross, respectively. From a hunter's perspective, that's a big difference, and tends to reduce their enjoyment and satisfaction with their management strategy. But in theory, this is just a small problem in management "results" which really does little long-term genetic harm to the deer population.
However, there could be unforeseen biological problems. As I mentioned, small-antlered young bucks in the Southeast are often late-born and/or the sons of lower dominance mothers ("poorer" mothers). The largest antlered yearling bucks are generally earlier born and/or the offspring of more dominant, "better" mothers. If an Antler Point Restriction is removing these larger-antlered yearlings at a much higher rate, while protecting the smaller-antlered young bucks, what "genetic material" is being selectively removed from the population? If those larger-antlered yearling bucks are the offspring of more dominant mothers--and dominance should be tightly linked to specific genetic traits--those genetic traits for dominance may be being completely removed from the herd.
Natural Selection is a very misunderstood process. It is often termed "survival of the fittest." However, that isn't exactly accurate. It should be described as: "He/She who produces the most surviving offspring wins." Natural Selection--when it is functioning properly--is actual a system by which "good" genetics are passed on through reproduction to the later generations of a species at a higher rate than "poor" genetics. It does this by allowing the individual animals with the "best" genetics to 1) survive through reproductive age; and 2) produce the most surviving offspring. The process by which these occur is the dominance process. "Good" genetic traits will be linked to genetic traits for dominance. If an Antler Point Restriction is removing bucks who had mothers that were more dominant, then that Antler Point Restriction is removing exactly the bucks that Nature wants to favor through Natural Selection. This means that the Antler Point Restriction is working against Nature and it's Natural Selection process.