The culling of bucks has been a key component in the era of deer management in Texas. It is done either to take mouths off the range or tighten the buck/doe ratio, or the mindset is that by removing inferior quality bucks it would improve the overall genetics of the herd.
Has it made a difference? For removing deer to reduce mouths or improve sex ratios, yes. If the goal was to improve genetics, the answer according to a 13-year study of deer in the wild, the answer is no, and that is going to come as a shock to many.
The study was conducted on the Comanche Ranch in Maverick and Dimmit counties in a joint effort between the ranch, Texas A&M-Kingsville and the Caesar Kleberg Wildlife Research Institute. It was a massive effort using helicopters to capture 3,328 bucks a total of 7,095 times across three differently managed pastures.
A 3,500-acre pasture was under intensive management where yearlings with less than 6 points were removed, 2½ year olds with less than 8 points were taken, 3½ and 4½ year olds with less than 9 points were removed along with all buck 5½ scoring less than 145.
An 18,000-acre pasture was under a moderate plan where bucks 3½ and older were culled using the same criteria as the first pasture for that age-class.
The third was a 5,000-acre control pasture with no culling.
For the first seven years helicopters were used to capture bucks in each pasture. Those from the intensively and moderately managed pastures that did not measure up were harvested. Those released were aged, weighed, measured, sampled for DNA and implanted with a microchip identifier.
The culling aspect of the research was stopped after seven years because the impact in the intensively managed pasture resulted in the removal of an average of 93 percent of the yearlings annually, crashing the buck population.
However, trapping and data collection were continued and there was no significant change in average antler quality compared to the other pastures. Negative impacts in the pasture included the herd expanding from a 1:1 buck/doe ratio to 1:6. Also there was not enough bucks in the herd to breed the doe early, resulting in an increased number of late fawns that were smaller antlered as yearlings, despite having been sired by quality bucks.
Without culling the youngest deer the moderate pasture did not see the complete loss of those age classes, but it also did not see an increase in average scores compared to the other pastures.
It would be expected that if culling had a significant impact that the research would see fewer inferior deer each following year, but that was not the case.
“My thought is that it is liberating to us because we no longer worry about the individual deer effect on the herd,” said Donnie Draeger, wildlife director at the Comanche Ranch and a principal in the research. “If we have a 6-point, we are not worried that it is going to ruin the herd by passing on its genetic, or if we have a buck that is really big that we have to let live to 6, 7 and 8 years old to pass on its genetics. When can we take him at his best.”
Using DNA and being able to follow lineage at least three generations the study showed there was some correlation in the “big deer produce big deer” concept, but it is not a certainty. Although he doesn’t like anecdotal data, Draeger pointed out two examples as proof.
“We had one buck that was 190 at his peak. He sired several male offspring over the years and the best was 145,” he noted. In contrast there was a 140-class buck, slightly above average for a mature South Texas deer, whose offspring consistently scored more than 20 inches above the average for all other bucks in their age group.
Rainfall, or the lack of, plays a big role in the quality of nutrition in South Texas. It is a huge component in the ups and downs of antler quality one year to the next, and the study saw mature buck quality yo-yo back and forth depending on annual range conditions.
The research also showed there was a 12- to 15-inch average increase in antler quality one particular year over the previous year, but it was in all three pastures. The difference was rainfall, one factor that kept popping up in the study.
Not surprisingly, the research results have produced a variety of opinions from deer hunters and landowners.
“It runs the gamut of emotions from utter disbelieve and denial that it can’t be true, my eyes forsake my brain, to oh my God, now what do we do,” Draeger said.
For those who say they have been culling for years and seen a difference, Draeger suspects that with their harvest program they have done other things like supplemental feed or numbers reduction, and are giving credit to the culling and not the improved nutrition.
For those who cull every 8-point and below, and argue they now only see 10-pointers he argues they have not changed the genetics, they just continue to remove a segment of the population.
This study did not look at the theory that a spike yearling will continue to be an inferior deer throughout its lifetime. A previous study on the King Ranch already concluded that while a yearling spike may not grow as big as it fork-antlered cohorts, they do have the ability to catch up later in life to become at least average sized for the region.
In culling, hunters only have antlers quality to determine what should go. The wildcards include the genetics of the doe and dormant genetics in the bucks, something similar to 5-foot-5 human parents producing a 6-foot-3 off-spring.
So what is necessary to produce quality deer? The boring, but tried and true plan.
“Because everyone is different I give a generic answer. If you maintain carrying capacity, maintain proper buck/doe ratio at 1:1 or 1:2, have age structure and let young bucks walk, if you did all three of those things you would probably put most wildlife biologist out of business,” Draeger said.
The biologist added, “I am not saying culling is bad. It works if your goal is to reduce mouths or lower your feed bill. If it is to change your herd genetically it does not work.”