fact or fiction?

[deernut]

Man, this is a complicated topic. I have been following it ever since doing my graduate work in South Texas on trophy whitetails and then as Chief of Wildlife Operations on the Rio Paisano Ranch south of Corpus Christi. There seems to be 2 "camps" of researchers on this topic: one in Texas based on the work at the Kerr Wildlife Management Area and the other camp originally centered around Dr. Harry Jacobson at Mississippi State University. After leaving S.TX, I went to work for Dr. Jacobson at MSU so I had first-hand knowledge of working in both "Camps." You would think that would give me insight and clarity to explain to everyone what the real deal is. The truth is there is good research on both sides and that has lead to confusion and apparently conflicting results. The studies were designed a little differently and analyzed differently so some of the differences may just be due to the different ways they conducted the research. Still, more advanced studies (like the Kroll & Koerth study linked above) continue to add to the confusion. Better and better studies are coming up with still different results. I know almost all the people involved personnally and they are solid researchers and all right to some degree (and wrong to some degree).

 

I'm currently 2/3rds of the way through writing a 3-part series on the Role of Genetics in Deer Management and can't post it all here before it is published. The series addresses this topic in more detail than I have seen elsewhere. I can include an excerpt from Part 1:

 

Starting in 1973, Donnie Harmel, John Williams, William Armstrong, Jim Ott, and others began a series of progressively more complex experiments on the effects of genetics and nutrition on antler and body size in whitetails on the Kerr Wildlife Management Area. In the first experiment, 8 bucks that were spikes as yearlings and 1 buck that was a large 10-point at 3.5 years old were bred to does and the antler development of 10 generations of offspring were recorded. Researchers showed that antler size and body weight were genetically based and influenced by environmental factors like nutrition. Data collected from this captive population indicated a buck’s future antler size could be predicted by looking at his first set of antlers. On the average, bucks carrying spike antlers when they were yearlings did not grow antlers as big as those that were forked-antlered yearlings. Yearling spikes also went on to produce more spike-antlered offspring in their lifetime than bucks with forked antlers as yearlings. A more intensive analysis of the inheritance of antler characteristics was later conducted on these captive deer and most antler characters were considered to have high levels of heritability.

 

The early studies from Kerr WMA set off the “spike wars.” If spikes were prone to producing and passing on inferior antler genes then removing spikes might be a way to cleanse the gene pool. The widespread slaughter of spikes commenced in the name of genetic purity. One of the reasons this “Gene-ocide” became so popular, so fast, was that it was fun. Finally, there was something we could actively do to improve the gene pool -- and it involved shooting deer! However, as more information became available, the idea of genetic improvement became more complex and managers were understandably confused.

 

During this time I was completing my Master’s Degree at Texas A&M-Kingsville under Drs. Sam Beasom and Charlie DeYoung and then managing the Rio Paisano Ranch in Brooks County. This spike culling made all the sense in the world and we killed spikes on the ranch at every opportunity. I then started working for Dr. Harry Jacobson at Mississippi State University and Jacobson was giving talks and showing pictures from his captive deer herd that showed some spikes that became tremendous bucks at maturity!

 

Some people started to point out that poor nutrition and late birth dates will also produce spike antlers in a yearling irrespective of what kind of genetics the buck has. Removing those deer would not improve genetics and may even be counterproductive. In some areas of the country with chronically poor nutrition, most yearling bucks are spikes and if culled intensively, deer managers could nearly wipe out the yearling age class. When it comes to gene pools you don’t want to drain it in order to clean it.

 

There were criticisms that Jacobson’s anecdotal slides showing a spike-to-monster progression was not data, but simply pictures of the exceptions. So Jacobson teamed up with geneticist Steven Lukefahr to conduct an analysis of antler measurements and pedigrees of over 200 captive white-tailed deer housed at Mississippi State. Analysis of this herd from 1977 to 1993 indicated that the occurrence of spike antlers in yearling bucks was related more to environmental factors than genetics. Antler characteristics of yearlings are probably more dependent on nutrition and birth date (early or late born) because when their bodies are still growing and nutrients available for antler growth may be limited. The genetic influence of antler conformation was more detectable in older bucks (2+ years); as their bodies matured, antler size was related more to their genetic potential than their nutritional intake.

 

The Mississippi data and the Texas data yielded what looks like contradictory results, which has led to decades of controversy. According to an independent review by Texas A&M animal geneticist Daniel Waldron, the different conclusions derived from these research efforts may simply be the result of the researchers asking slightly different questions and analyzing their data with different statistical methods. Dr. Waldron also pointed out that some Kerr WMA studies did not account for factors such as the birth date of yearling bucks, year, maternal influences, or the fact that many of the sires in the Kerr herd were related to one exceptional sire buck. The Mississippi captive herd consisted of deer from the Midwest and Southeast and this may be a problem when applying the conclusions to Texas deer. Waldron felt that neither the Texas nor the Mississippi analyses resolved this issue definitively.

 

It seems logical that during a buck’s first year of growth, nutritional variation would have a lot to do with the size of his first set of antlers. And yet, the Kerr data showed clearly that the antler size at the yearling stage does hold some predictive value in what that animal’s antlers will look like at maturity.

 

I cover this all in Chapter 4 of my book (Factors affecting antler size, Page 80-84). I also have a table on Page 82 that shows that 85% of spikes are yearlings and 35% of 2x2s are yearlings. This is over several years and would vary dramatically due to the amount of rain in any given year as a few of you mentioned above.

 

So, there's a lot of information, but not a lot of answers. As I go on to write later in the series, none of this matters much because hunters can't exert enough influence on the gene pool of a free-ranging deer population to affect the gene pool so the idea of culling to improve the genes is bogus except under very very extreme culling in a captive or small and contained population.

 

JIM

[CouesWhitetail]

Thanks for all the info Jim!!

 

Amanda

 

[WFGinNM]

Thanks for the info Jim, very good stuff. I'll be sending off an order for your book soon.

 

Take care,

 

--Bill