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White-tailed Deer

Importing Brood Bucks

The information presented on this page is published in Understanding Spike Buck Harvestmedia download(PDF 2 MB) (by Bill Armstrong, Kerr Wildlife Management Area, TPWD).

Do I need to buy a "Brood Buck" to produce big deer on my ranch?

The answer is simple... No, you do not. In most cases, it's simply a waste of time and money. There are a few reasons for this answer.

Data Table

(Reason 1) Most populations of deer contain animals with good genetic potential (Figure 1). With a combination of good habitat management and selective harvest (phenotypic selection), substantial herd improvement can occur. Obviously larger ranches with more animals to choose from have a statistical advantage for gain. However, smaller ranches (500 to 1500 acres) can usually do a better job of selection than larger ranches simply because selection can be more intense (with fewer animals).

(Reason 2) A buck grown under a controlled set of conditions (a pen with pelleted feed) or a buck from a different habitat type may not perform well under a changed set of conditions.

For example: It is known that it takes 2 parts calcium to 1 part phosphorus to grow bone tissue. If a range produces adequate amounts of calcium but not enough phosphorus, not all the calcium can be utilized for bone growth. We do not know the exact genes involved in antler growth but let us hypothesize that a set of genes affects phosphorus absorption and storage. In a pen situation where more than adequate phosphorus was present, the antlers would look good. Now suppose that this deer were placed on a phosphorus-poor range and the deer did not get adequate phosphorus. This deer would not produce good antlers. In a ranchers' term, the deer "fell apart" without extra phosphorus. The ability to utilize phosphorus efficiently may be genetic while not having adequate phosphorus is nutritional. These traits would be passed to its offspring.

In management, the selection for those animals that perform well under range conditions on a given ranch under a given set of environmental conditions is important for antler production. Selecting for those animals that perform well under less than optimal conditions is an important component in genetic selection.

(Reason 3) A male deer contributes 50% of the genetic material for antler development. We don't know what genes/alleles contribute to antler development. Hypothetical: However, let's suppose that a male has a set of allelic genes that consists of 2 genes. One for a large amount of mass we will call "M", and the other gene may be for a small amount of mass that we will call little "m." We will also assume that big "M" is dominate over little "m." The female also contributes 50% and let's assume her genes for antler mass were "mm". If male Mm and female mm bred, then the phenotypic range of possible offspring would be either Mm, Mm, or mm. Some good quality offspring or some poor quality offspring could be produced. Those poor quality offspring must then be removed from the population. If an Mm male and an Mm female bred, the possible genes of the offspring would be MM, Mm, Mm, mm. In this scenario, three deer with good mass potential would be produced and one deer with poor mass potential would be produced. The MM deer would always produce good phenotypic offspring. However, the Mm may not always produce big antlered offspring. As more MM deer are produced, the overall population of deer will be improved for mass.

Again the important factor in producing a herd with good antlers is the selection process to eliminate small antlered offspring and leave good antlered offspring. Older does must also be removed to insure that younger does are from the better quality males. Selection is the more important part of the management process; no matter who the original sire was. Most ranges have enough genetic variability to produce quality deer with selection. In geneticists' terms selection is increasing the gene frequency for large antlers.

The following actual example demonstrates the effectiveness of a "high quality brood buck".

Photo of Brood Buck

In 1993, a 4.5-year-old buck was used as a sire on a select group of does. This buck at 7.5 years had 22 points, an outside spread of 30.25 inches, and an inside spread of 26.125 inches. His Boone & Crockett score was 205 gross and 193 net.

This mating produced 11 male fawns in 1994. At 1.5 years the antler development of these bucks was as follows: one had 7 points, one had 6 points, one had 3 points, and eight were spikes. All of these yearling offspring were grown on an 8% limited diet. They were then placed on a free choice 16% diet. At 2.5 years, four had 8 points, three had 7 points, three had 6 points and one had 4 points. At 3.5 years, two had 9 points, five have 8 points, and four had 7 points. Antler production of the offspring from this 200+ class buck was well below average for a simple reason. The reason is that the select group of does were spike line does from the spike line study. Speculation: The buck was probably relatively heterozygous for most of its antler traits. When bred to does which were mostly homozygous for spike antlers, a large number of the offspring became homozygous for poor antlers.

Bringing in "trophy bucks" once the selection process has begun will probably dilute the gain made from selection and the process will need to begin again.